This is the documentation for the Part Ontology. All instances of the Part class are listed here. The part class is reserved for concepts that can be applied to a Body or an Abstraction, but that in and of themselves do not hold meaning. Examples include bottom and top. Entities that sufficiently describe concepts in and of themselves but that are parts of other concepts are attached to those concepts using the context construct.

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Documentation last generated on 2019-04-29 13:05 EDT.

ablation-zone

This instance has a related Wikipedia page. Short extract:
Ablation zone or ablation area refers to the low-altitude area of a glacier or ice sheet below firn with a net loss in ice mass due to melting, sublimation, evaporation, ice calving, aeolian processes like blowing snow, avalanche, and any other ablation. The equilibrium line altitude (ELA) or snow line separates the ablation zone from the higher-altitude accumulation zone.

This instance is a narrower concept derived from zone.

accumulation-zone

This instance has a related Wikipedia page. Short extract:
On a glacier, the accumulation zone is the area above the firn line, where snowfall accumulates and exceeds the losses from ablation, (melting, evaporation, and sublimation). The annual equilibrium line separates the accumulation and ablation zone annually.

This instance is a narrower concept derived from zone.

active-layer

This instance has a related Wikipedia page. Short extract:
In environments containing permafrost, the active layer is the top layer of soil that thaws during the summer and freezes again during the autumn. In all climates, whether they contain permafrost or not, the temperature in the lower levels of the soil will remain more stable than that at the surface, where the influence of the ambient temperature is greatest.

This instance is a narrower concept derived from layer.

amphidromic-points

This instance has a related Wikipedia page. Short extract:
An amphidromic point, also called a tidal node, is a geographical location which has zero tidal amplitude for one harmonic constituent of the tide. The tidal range (the peak-to-peak amplitude, or height difference between high tide and low tide) for that harmonic constituent increases with distance from this point.The term amphidromic point derives from the Greek words amphi (around) and dromos (running), referring to the rotary tides running around them.

This instance is a narrower concept derived from points.

This instance has the following attributes:

apex

This instance has a related Wikipedia page. Short extract:
In geometry, an apex (Latin for 'summit, peak, tip, top, extreme end') is the vertex which is in some sense the "highest" of the figure to which it belongs.

This instance is a narrower concept derived from point.

aphelion

This instance has a related Wikipedia page. Short extract:
Apsis (Greek: ἁψίς; plural apsides , Greek: ἁψῖδες; "orbit") denotes either of the two extreme points—ie, the farthest or nearest point—in the orbit of a planetary body about its primary body (or simply, "the primary"). The plural term, "apsides", usually implies both apsis points (i.e., farthest and nearest); apsides can also refer to the distance of the extreme range of an object orbiting a host body.

This instance is a narrower concept derived from point.

band

base

bed

This instance has a related Wikipedia page. Short extract:
A bed is a piece of furniture.

beds

This instance is a plurality of bed.

beds~bottomset

This instance has the following attributes:

beds~foreset

This instance has the following attributes:

beds~topset

This instance has the following attributes:

beds~topset~lower

This instance is a narrower concept derived from beds~topset.

This instance has the following attributes:

beds~topset~upper

This instance is a narrower concept derived from beds~topset.

This instance has the following attributes:

bottom

boundary

Alternative labels for this instance are: contour.

This instance has a related Wikipedia page. Short extract:
In topology and mathematics in general, the boundary of a subset S of a topological space X is the set of points which can be approached both from S and from the outside of S. More precisely, it is the set of points in the closure of S not belonging to the interior of S. An element of the boundary of S is called a boundary point of S. The term boundary operation refers to finding or taking the boundary of a set. Notations used for boundary of a set S include bd(S), fr(S), and ∂S. Some authors (for example Willard, in General Topology) use the term frontier instead of boundary in an attempt to avoid confusion with the concept of boundary used in algebraic topology and manifold theory.

This instance is a narrower concept derived from point-set.

boundary~core-mantle

This instance has a related Wikipedia page. Short extract:
The core–mantle boundary (CMB in the parlance of solid earth geophysicists) of the Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2891 km (1796 mi) depth beneath the Earth's surface.

This instance is a narrower concept derived from boundary.

This instance has the following attributes:

boundary~crust-mantle

This instance is a narrower concept derived from boundary.

This instance has the following attributes:

boundary~lithosphere-asthenosphere

This instance has a related Wikipedia page. Short extract:
The Lithosphere–asthenosphere boundary (LAB) represents a mechanical difference between layers in Earth's inner structure. Earth's inner structure can be described both chemically (crust, mantle, core) and mechanically.

This instance is a narrower concept derived from boundary.

This instance has the following attributes:

boundary~seaward

This instance is a narrower concept derived from boundary.

This instance has the following attributes:

boundary-layer

This instance has a related Wikipedia page. Short extract:
In physics and fluid mechanics, a boundary layer is an important concept and refers to the layer of fluid in the immediate vicinity of a bounding surface where the effects of viscosity are significant. In the Earth's atmosphere, the atmospheric boundary layer is the air layer near the ground affected by diurnal heat, moisture or momentum transfer to or from the surface.

This instance is a narrower concept derived from layer.

canopy

This instance has a related Wikipedia page. Short extract:
Canopy may refer to:

cell

This instance is a narrower concept derived from partition.

cell~dual

This instance is a narrower concept derived from cell.

This instance has the following attributes:

cell~primary

This instance is a narrower concept derived from cell.

This instance has the following attributes:

center

This instance has a related Wikipedia page. Short extract:
In geometry, a center (or centre) (from Greek κέντρον) of an object is a point in some sense in the middle of the object. According to the specific definition of center taken into consideration, an object might have no center If geometry is regarded as the study of isometry groups then a center is a fixed point of all the isometries which move the object onto itself.

This instance is a narrower concept derived from point.

centerline

This instance is a narrower concept derived from line.

centroid

This instance has a related Wikipedia page. Short extract:
In mathematics and physics, the centroid or geometric center of a plane figure is the arithmetic mean position of all the points in the figure. Informally, it is the point at which a cutout of the shape could be perfectly balanced on the tip of a pin.The definition extends to any object in n-dimensional space: its centroid is the mean position of all the points in all of the coordinate directions.While in geometry the word barycenter is a synonym for centroid, in astrophysics and astronomy, the barycenter is the center of mass of two or more bodies that orbit each other.

This instance is a narrower concept derived from point.

column

This instance has a related Wikipedia page. Short extract:
In linear algebra, the column space (also called the range or image) of a matrix A is the span (set of all possible linear combinations) of its column vectors. The column space of a matrix is the image or range of the corresponding matrix transformation.

This instance is a narrower concept derived from partition.

component

Alternative labels for this instance are: part.

constituent

Alternative labels for this instance are: part.

This instance has a related Wikipedia page. Short extract:
Part, parts or PART may refer to:

constituent~2mk3

This instance is a narrower concept derived from constituent.

constituent~2n2

This instance is a narrower concept derived from constituent.

constituent~2q1

This instance is a narrower concept derived from constituent.

constituent~2sm2

This instance is a narrower concept derived from constituent.

constituent~j1

This instance is a narrower concept derived from constituent.

constituent~k1

This instance is a narrower concept derived from constituent.

constituent~k2

This instance is a narrower concept derived from constituent.

constituent~l2

This instance is a narrower concept derived from constituent.

constituent~lam2

This instance is a narrower concept derived from constituent.

constituent~m1

This instance is a narrower concept derived from constituent.

constituent~m2

This instance is a narrower concept derived from constituent.

constituent~m3

This instance is a narrower concept derived from constituent.

constituent~m4

This instance is a narrower concept derived from constituent.

constituent~m6

This instance is a narrower concept derived from constituent.

constituent~m8

This instance is a narrower concept derived from constituent.

constituent~mf

This instance is a narrower concept derived from constituent.

constituent~mk3

This instance is a narrower concept derived from constituent.

constituent~mm

This instance is a narrower concept derived from constituent.

constituent~mn4

This instance is a narrower concept derived from constituent.

constituent~ms4

This instance is a narrower concept derived from constituent.

constituent~msf

This instance is a narrower concept derived from constituent.

constituent~mu2

This instance is a narrower concept derived from constituent.

constituent~n2

This instance is a narrower concept derived from constituent.

constituent~nu2

This instance is a narrower concept derived from constituent.

constituent~o1

This instance is a narrower concept derived from constituent.

constituent~oo1

This instance is a narrower concept derived from constituent.

constituent~oo2

This instance is a narrower concept derived from constituent.

constituent~p1

This instance is a narrower concept derived from constituent.

constituent~q1

This instance is a narrower concept derived from constituent.

constituent~r2

This instance is a narrower concept derived from constituent.

constituent~rho

This instance is a narrower concept derived from constituent.

constituent~s1

This instance is a narrower concept derived from constituent.

constituent~s2

This instance is a narrower concept derived from constituent.

constituent~s4

This instance is a narrower concept derived from constituent.

constituent~s6

This instance is a narrower concept derived from constituent.

constituent~sa

This instance is a narrower concept derived from constituent.

constituent~ssa

This instance is a narrower concept derived from constituent.

constituent~t2

This instance is a narrower concept derived from constituent.

constituents

This instance is a plurality of constituent.

constituents~all

This instance is a narrower concept derived from constituents.

This instance has the following attributes:

contour

Alternative labels for this instance are: isocline.

This instance has a related Wikipedia page. Short extract:
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function f(x, y) parallel to the x, y plane.

This instance is a narrower concept derived from point-set.

core

This instance has a related Wikipedia page. Short extract:
Core may refer to:

core~inner

This instance is a narrower concept derived from core.

This instance has the following attributes:

core~outer

This instance is a narrower concept derived from core.

This instance has the following attributes:

crest

This instance has a related Wikipedia page. Short extract:
A crest is the point on a wave with the maximum value of upward displacement within a cycle. A crest is a point on a surface wave where the displacement of the medium is at a maximum.

crest_x-section

This abstraction represents crest as abstracted by x-section.

crest_x-section_vertex

This abstraction represents crest_x-section as abstracted by vertex.

crestline

This instance is a narrower concept derived from line.

crust

This instance has a related Wikipedia page. Short extract:
Crust may refer to:

datum~vertical

This instance is a narrower concept derived from datum.

This instance has the following attributes:

datum~vertical~geodetic

This instance is a narrower concept derived from datum%257Evertical.

This instance has the following attributes:

datum~vertical~gravimetric

This instance is a narrower concept derived from datum%257Evertical.

This instance has the following attributes:

datum~vertical~tidal

This instance is a narrower concept derived from datum%257Evertical.

This instance has the following attributes:

datum~vertical~tidal~msl

This instance is a narrower concept derived from datum%257Evertical%257Etidal.

This instance has the following attributes:

edge

This instance has a related Wikipedia page. Short extract:
For edge in graph theory, see Edge (graph theory)In geometry, an edge is a particular type of line segment joining two vertices in a polygon, polyhedron, or higher-dimensional polytope. In a polygon, an edge is a line segment on the boundary, and is often called a side.

edge~east

This instance is a narrower concept derived from edge.

This instance has the following attributes:

edge~leading-displaced-convection

This instance is a narrower concept derived from edge.

edge~north

This instance is a narrower concept derived from edge.

This instance has the following attributes:

edge~south

This instance is a narrower concept derived from edge.

This instance has the following attributes:

edge~west

This instance is a narrower concept derived from edge.

This instance has the following attributes:

edge~x

This instance is a narrower concept derived from edge.

This instance has the following attributes:

edge~y

This instance is a narrower concept derived from edge.

This instance has the following attributes:

endpoint

This instance has a related Wikipedia page. Short extract:
An endpoint, end-point or end point may refer to:

This instance is a narrower concept derived from point.

endpoint~downstream

This instance is a narrower concept derived from endpoint.

This instance has the following attributes:

endpoint~upstream

This instance is a narrower concept derived from endpoint.

This instance has the following attributes:

endpoints

This instance is a plurality of endpoint.

This instance has a related Wikipedia page. Short extract:
An endpoint, end-point or end point may refer to:

This instance is a narrower concept derived from points.

epicenter

This instance has a related Wikipedia page. Short extract:
The epicenter, epicentre or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates.

This instance is a narrower concept derived from point.

equator

This instance has a related Wikipedia page. Short extract:
An equator of a rotating spheroid (such as a planet) is its zeroth circle of latitude (parallel). It is the imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres.

This instance is a narrower concept derived from line.

equator_plane

This abstraction represents equator as abstracted by plane.

equilibrium-line

This instance is a narrower concept derived from line.

This instance has the following attributes:

face

face

This instance has a related Wikipedia page. Short extract:
In solid geometry, a face is a flat (planar) surface that forms part of the boundary of a solid object; a three-dimensional solid bounded exclusively by flat faces is a polyhedron. In more technical treatments of the geometry of polyhedra and higher-dimensional polytopes, the term is also used to mean an element of any dimension of a more general polytope (in any number of dimensions).

This instance is a narrower concept derived from shape.

floor

This instance has a related Wikipedia page. Short extract:
A floor is the bottom surface of a room or vehicle. Floors vary from simple dirt in a cave to many-layered surfaces modern technology.

foci

This instance is a plurality of focus.

This instance is a narrower concept derived from points.

focus

This instance has a related Wikipedia page. Short extract:
In geometry, focuses or foci (UK: , US: ), singular focus, are special points with reference to which any of a variety of curves is constructed. For example, one or two foci can be used in defining conic sections, the four types of which are the circle, ellipse, parabola, and hyperbola.

This instance is a narrower concept derived from point.

front

geocenter

This instance is a narrower concept derived from point.

geodesic

This instance has a related Wikipedia page. Short extract:
In differential geometry, a geodesic () is a curve representing in some sense the shortest path between two points in a surface, or more generally in a Riemannian manifold. It is a generalization of the notion of a "straight line" to a more general setting.

This instance is a narrower concept derived from line.

geoid

This instance is a narrower concept derived from model.

horizon

horizon~a

This instance is a narrower concept derived from horizon.

horizon~b

This instance is a narrower concept derived from horizon.

horizon~c

This instance is a narrower concept derived from horizon.

horizon~d

This instance is a narrower concept derived from horizon.

horizon~e

This instance is a narrower concept derived from horizon.

horizon~l

This instance is a narrower concept derived from horizon.

horizon~o

This instance is a narrower concept derived from horizon.

horizon~p

This instance is a narrower concept derived from horizon.

horizon~r

This instance is a narrower concept derived from horizon.

hypocenter

Alternative labels for this instance are: focus.

This instance has a related Wikipedia page. Short extract:
A hypocenter (or hypocentre) (from Ancient Greek: ὑπόκεντρον [hypόkentron] for 'below the center') is the point of origin of an earthquake or a subsurface nuclear explosion. In seismology, it is a synonym of the focus.

This instance is a narrower concept derived from point.

interior

isocline

This instance has a related Wikipedia page. Short extract:
A contour line (also isoline, isopleth, or isarithm) of a function of two variables is a curve along which the function has a constant value, so that the curve joins points of equal value. It is a plane section of the three-dimensional graph of the function f(x, y) parallel to the x, y plane.

This instance is a narrower concept derived from line.

isopycnal-layer

This instance is a narrower concept derived from layer.

isosurface

This instance has a related Wikipedia page. Short extract:
An isosurface is a three-dimensional analog of an isoline. It is a surface that represents points of a constant value (e.g.

This instance is a narrower concept derived from surface.

isosurface~potential-temperature

This instance is a narrower concept derived from isosurface.

This instance has the following attributes:

land-mask

This instance is a narrower concept derived from mask.

This instance has the following attributes:

layer

This instance has a related Wikipedia page. Short extract:
Layer (in Sanskrit: "'कला"') or layered may refer to:

layer~0

This instance is a narrower concept derived from layer.

layer~1

This instance is a narrower concept derived from layer.

layer~2

This instance is a narrower concept derived from layer.

layer~base

This instance is a narrower concept derived from layer.

This instance has the following attributes:

layer~first

This instance is a narrower concept derived from layer.

This instance has the following attributes:

layer~second

This instance is a narrower concept derived from layer.

This instance has the following attributes:

layer~top

This instance is a narrower concept derived from layer.

This instance has the following attributes:

lead

location

This instance has a related Wikipedia page. Short extract:
In geography, location and place are used to identify a point or an area on the Earth's surface or elsewhere. The term location generally implies a higher degree of certainty than place, the latter often indicating an entity with an ambiguous boundary, relying more on human or social attributes of place identity and sense of place than on geometry.

location-1

This instance is a narrower concept derived from location.

location-2

This instance is a narrower concept derived from location.

location-3

This instance is a narrower concept derived from location.

location-4

This instance is a narrower concept derived from location.

location-5

This instance is a narrower concept derived from location.

location-6

This instance is a narrower concept derived from location.

mantle

middle

mixed-layer

This instance has a related Wikipedia page. Short extract:
The oceanic or limnological mixed layer is a layer in which active turbulence has homogenized some range of depths. The surface mixed layer is a layer where this turbulence is generated by winds, surface heat fluxes, or processes such as evaporation or sea ice formation which result in an increase in salinity.

This instance is a narrower concept derived from layer.

neck

node

This instance is a narrower concept derived from point.

node~dual

This instance is a narrower concept derived from node.

This instance has the following attributes:

node~dual~x

This instance is a narrower concept derived from node%257Edual.

This instance has the following attributes:

node~dual~y

This instance is a narrower concept derived from node%257Edual.

This instance has the following attributes:

node~dual~z

This instance is a narrower concept derived from node%257Edual.

This instance has the following attributes:

node~primary

This instance is a narrower concept derived from node.

This instance has the following attributes:

node~primary~x

This instance is a narrower concept derived from node%257Eprimary.

This instance has the following attributes:

node~primary~y

This instance is a narrower concept derived from node%257Eprimary.

This instance has the following attributes:

node~primary~z

This instance is a narrower concept derived from node%257Eprimary.

This instance has the following attributes:

body

partition

This instance has a related Wikipedia page. Short extract:
In mathematics, a partition of an interval [a, b] on the real line is a finite sequence x0, x1, x2, ..., xk of real numbers such that a = x0 < x1 < x2 < ... < xk = b.In other terms, a partition of a compact interval I is a strictly increasing sequence of numbers (belonging to the interval I itself) starting from the initial point of I and arriving at the final point of I. Every interval of the form [xi, xi + 1] is referred to as a subinterval of the partition x.

perihelion

This instance has a related Wikipedia page. Short extract:
Apsis (Greek: ἁψίς; plural apsides , Greek: ἁψῖδες; "orbit") denotes either of the two extreme points—ie, the farthest or nearest point—in the orbit of a planetary body about its primary body (or simply, "the primary"). The plural term, "apsides", usually implies both apsis points (i.e., farthest and nearest); apsides can also refer to the distance of the extreme range of an object orbiting a host body.

This instance is a narrower concept derived from point.

photic-zone

This instance is a narrower concept derived from zone.

plug-layer

This instance has a related Wikipedia page. Short extract:
In fluid mechanics, plug flow is a simple model of the velocity profile of a fluid flowing in a pipe. In plug flow, the velocity of the fluid is assumed to be constant across any cross-section of the pipe perpendicular to the axis of the pipe.

This instance is a narrower concept derived from layer.

pole

This instance has a related Wikipedia page. Short extract:
The poles of astronomical bodies are determined based on their axis of rotation in relation to the celestial poles of the celestial sphere. Astronomical bodies include stars, planets, dwarf planets and small Solar System bodies such as comets and minor planets (i.e.

This instance is a narrower concept derived from point.

pole~north

This instance has a related Wikipedia page. Short extract:
North Pole may refer to:

This instance is a narrower concept derived from pole.

This instance has the following attributes:

pole~north~magnetic

This instance has a related Wikipedia page. Short extract:
The North Magnetic Pole is the wandering point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downwards (in other words, if a magnetic compass needle is allowed to rotate about a horizontal axis, it will point straight down). There is only one location where this occurs, near (but distinct from) the Geographic North Pole and the Geomagnetic North Pole.

This instance is a narrower concept derived from pole%257Enorth.

This instance has the following attributes:

pole~north~terrestrial

This instance has a related Wikipedia page. Short extract:
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is (subject to the caveats explained below) defined as the point in the Northern Hemisphere where the Earth's axis of rotation meets its surface. The North Pole is the northernmost point on the Earth, lying diametrically opposite the South Pole.

This instance is a narrower concept derived from pole%257Enorth.

This instance has the following attributes:

pole~north~virtual

This instance is a narrower concept derived from pole%257Enorth.

This instance has the following attributes:

pole~south

This instance has a related Wikipedia page. Short extract:
South Pole may refer to:

This instance is a narrower concept derived from pole.

This instance has the following attributes:

pole~south~magnetic

This instance has a related Wikipedia page. Short extract:
The South Magnetic Pole is the wandering point on Earth's Southern Hemisphere where the geomagnetic field lines are directed vertically upwards. It should not be confused with the South Geomagnetic Pole described later.

This instance is a narrower concept derived from pole%257Esouth.

This instance has the following attributes:

pole~south~terrestrial

This instance has a related Wikipedia page. Short extract:
The South Pole, also known as the Geographic South Pole or Terrestrial South Pole, is one of the two points where Earth's axis of rotation intersects its surface. It is the southernmost point on the surface of Earth and lies on the opposite side of Earth from the North Pole.

This instance is a narrower concept derived from pole%257Esouth.

This instance has the following attributes:

region

This instance has a related Wikipedia page. Short extract:
In geography, regions are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and the environment (environmental geography). Geographic regions and sub-regions are mostly described by their imprecisely defined, and sometimes transitory boundaries, except in human geography, where jurisdiction areas such as national borders are defined in law.

region~central-dense-overcast

This instance is a narrower concept derived from region.

This instance has the following attributes:

region~cloud

This instance is a narrower concept derived from region.

This instance has the following attributes:

region~eye

This instance is a narrower concept derived from region.

This instance has the following attributes:

regolith-layer

This instance has a related Wikipedia page. Short extract:
Regolith () is a layer of loose, heterogeneous superficial deposits covering solid rock. It includes dust, soil, broken rock, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons.

This instance is a narrower concept derived from layer.

root-zone

This instance has a related Wikipedia page. Short extract:
The rhizosphere is the narrow region of soil that is directly influenced by root secretions, and associated soil microorganisms known as the root microbiome. The rhizosphere contains many bacteria and other microorganisms that feed on sloughed-off plant cells, termed rhizodeposition, and the proteins and sugars released by roots.

This instance is a narrower concept derived from zone.

row

This instance has a related Wikipedia page. Short extract:
In linear algebra, the column space (also called the range or image) of a matrix A is the span (set of all possible linear combinations) of its column vectors. The column space of a matrix is the image or range of the corresponding matrix transformation.

This instance is a narrower concept derived from partition.

sat-zone

This instance has a related Wikipedia page. Short extract:
The phreatic zone, or zone of saturation, is the area in an aquifer, below the water table, in which relatively all pores and fractures are saturated with water. The phreatic zone defines the lower edge of the vadose zone.

This instance is a narrower concept derived from zone.

This instance has the following attributes:

sea-mask

This instance is a narrower concept derived from mask.

This instance has the following attributes:

segment

This instance has a related Wikipedia page. Short extract:
Segment or segmentation may refer to:

shaft

shear-layer

This instance has a related Wikipedia page. Short extract:
The term shear flow is used in solid mechanics as well as in fluid dynamics. The expression shear flow is used to indicate: a shear stress over a distance in a thin-walled structure (in solid mechanics); the flow induced by a force (in a fluid).

This instance is a narrower concept derived from layer.

shell

shoreline

This instance is a narrower concept derived from line.

shoreline_axis~x

This abstraction represents shoreline as abstracted by axis%257Ex.

side

This instance has a related Wikipedia page. Short extract:
Side or Sides may refer to:

side~left

This instance is a narrower concept derived from side.

This instance has the following attributes:

side~right

This instance is a narrower concept derived from side.

This instance has the following attributes:

skin

This instance has a related Wikipedia page. Short extract:
Skin is a soft outer covering of an animal, in particular a vertebrate.

stratum

Alternative labels for this instance are: layer.

This instance has a related Wikipedia page. Short extract:
In geology and related fields, a stratum (plural: strata) is a layer of sedimentary rock or soil, or igneous rock that were formed at the Earth's surface, with internally consistent characteristics that distinguish it from other layers. The "stratum" is the fundamental unit in a stratigraphic column and forms the basis of the study of stratigraphy.

subskin

subsurface

surface

This instance has a related Wikipedia page. Short extract:
In mathematics, a surface is a generalization of a plane which needs not be flat – that is, the curvature is not necessarily zero. This is analogous to a curve generalizing a straight line.

surface_viewpoint

This abstraction represents surface as abstracted by viewpoint.

target

This instance is a narrower concept derived from point.

terminus

toe

top

tops

This instance is a plurality of top.

trough

This instance has a related Wikipedia page. Short extract:
A crest is the point on a wave with the maximum value of upward displacement within a cycle. A crest is a point on a surface wave where the displacement of the medium is at a maximum.

unsat-zone

This instance has a related Wikipedia page. Short extract:
The vadose zone, also termed the unsaturated zone, is the part of Earth between the land surface and the top of the phreatic zone, the position at which the groundwater (the water in the soil's pores) is at atmospheric pressure ("vadose" is from the Latin for "shallow"). Hence, the vadose zone extends from the top of the ground surface to the water table.

This instance is a narrower concept derived from zone.

This instance has the following attributes:

vertex

This instance has a related Wikipedia page. Short extract:
In geometry, a vertex (plural: vertices or vertexes) is a point where two or more curves, lines, or edges meet. As a consequence of this definition, the point where two lines meet to form an angle and the corners of polygons and polyhedra are vertices.

This instance is a narrower concept derived from point.

viewpoint

This instance has a related Wikipedia page. Short extract:
Two figures in a plane are perspective from a point O if the lines joining corresponding points of the figures all meet at O. Dually, the figures are said to be perspective from a line if the points of intersection of corresponding lines all lie on one line. The proper setting for this concept is in projective geometry where there will be no special cases due to parallel lines since all lines meet.

This instance is a narrower concept derived from point.

wheelbase

This instance has a related Wikipedia page. Short extract:
In both road and rail vehicles, the wheelbase is the distance between the centers of the front and rear wheels. For road vehicles with more than two axles (e.g.

This instance is a narrower concept derived from line.

wingspan

This instance has a related Wikipedia page. Short extract:
The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the other wingtip. For example, the Boeing 777-200 has a wingspan of 60.93 metres (199 ft 11 in), and a wandering albatross (Diomedea exulans) caught in 1965 had a wingspan of 3.63 metres (11 ft 11 in), the official record for a living bird.

This instance is a narrower concept derived from line.

x-section

Alternative labels for this instance are: cross-section.

This instance has a related Wikipedia page. Short extract:
In geometry and science, a cross section is the non-empty intersection of a solid body in three-dimensional space with a plane, or the analog in higher-dimensional spaces. Cutting an object into slices creates many parallel cross sections.

x-section~horizontal

This instance is a narrower concept derived from x-section.

This instance has the following attributes:

x-section~horizontal_circle

This abstraction represents x-section%257Ehorizontal as abstracted by circle.

x-section~vertical

This instance is a narrower concept derived from x-section.

This instance has the following attributes:

x-section_parabola

This abstraction represents x-section as abstracted by parabola.

x-section_top

This instance has the following components:

x-section_trapezoid

This abstraction represents x-section as abstracted by trapezoid.

x-section_trapezoid_bottom

This instance has the following components:

x-section_trapezoid_side

This instance has the following components:

x-section_trapezoid_side~left

This instance has the following components:

x-section_trapezoid_side~right

This instance has the following components:

x-section_trapezoid_top

This instance has the following components:

zone

This instance has a related Wikipedia page. Short extract:
Zone or The Zone or In the Zone may refer to:

aphotic-zone

This instance has a related Wikipedia page. Short extract:
The aphotic zone (aphotic from Greek prefix ἀ- + φῶς "without light") is the portion of a lake or ocean where there is little or no sunlight. It is formally defined as the depths beyond which less than 1% of sunlight penetrates.

This instance is a narrower concept derived from zone.

surf-zone

This instance has a related Wikipedia page. Short extract:
As ocean surface waves come closer to shore they break, forming the foamy, bubbly surface called surf. The region of breaking waves defines the surf zone.

This instance is a narrower concept derived from zone.