Geometry Glossary Essay, Research Paper
Geometry Glossary
Acute angle
- an angle whose measure is greater than 0 but less than 90 degrees; see obtuse angle
Adjacent angles
- 2 nonstraight and nonzero angles that have a common side in the interior of the angle formed by the noncommon sides
Algorithm
- a sequence of steps leading to a desired end
Alternate exterior angles
- exterior angles on alternate sides of the transversal (not on the same parallel line)
Alternate interior angles
- ditto as above, only with interior angles
Altitude
- height
Altitude of a conic solid
- the length of a segment whose endpoints are the vertex and a point on the plane of the base that is perpendicular to the plane of the base
Altitude of a cylindric solid
- the distance between the planes of the bases
Altitude of a trapezoid
- the distance between the bases of a trapeziod
Altitude of a triangle
- the perpendicular segment from a vertex to the line containing the opposite side of a triangle
Ambiguous
- not stable; changing
Analytic geometry
- see coordinate geometry
Angle
- the union of 2 rays that have the same endpoint; measured in degrees or radians (trig.); the five types of angles are zero, acute, right, obtuse, and straight
Angle bisector
- a ray that is in the interior of an angle and forms two equal angles with the sides of that angle
Angle measure between a line and a plane
- the smallest of the angles formed when a line intersects a plane
Angle side
- one of the two rays forming an angle
Antecedent
- the ‘if’ part of a conditional; represented by p; aka hypothesis, given, problem; see consequent
Area
- the amount of space taken up in a plane by a figure
Arc
- a path from one node in a network to another; doesn’t have to be straight & can be more than 1 line between 2 nodes; part of a circle; see minor arc, major arc
Arc length
- the distance between an arc’s endpoints along the path of the circle
Area(F)
- the area of figure F
Automatic drawer
- a computer program that lets you build constructions
Axis
- the line containing the vertex of a conic solid and the center of the base
Base
- the side of an isoscoles triangle whose endpoints are the vertices of the base angles
Base angle
- the angle opposite one of the equilateral sides in an isoscoles triangle
Base angle of a trapezoid
- consecutive angles that share a base of a trapezoid
Base of a conic solid
- the planar region that forms the widest point of a conic solid; often labeled as the ‘bottom’ of the conic solid, it determines the exact shape of the conic solid
Base of a cylindric solid
- the original region and its translation image
Base of a trapezoid
- the parallel sides of a trapezoid
Biconditional
- a conditional and its converse where the converse is also true; uses the words if and only if; written pq
Bilateral symmetry
- see reflection symmetry
Bisector of an angle
- see angle bisector
Bisector pf a segment
- any plane, point or two-dimensional figure containing the the midpoint of the segment and no other points on that segment
Box
- a surface made up of rectangles; a rectangular parallelpided
Capacity
- see volume
Cartesian plane
- a coordinate plane
Center of a circle
- the point that all points in the circle are equidistant from
Center of a rotation
- the point where the two intersecting lines of a rotation meet
Center of gravity
- the mean of the coordinates of points in a figure, whether one, two, or three-dimensional
Central angle of a circle
- an angle whose vertex is the center of the circle
Chord of a circle
- a segment whose endpoints are on a circle
Circle
- the set of points on a plane at a certain distance (radius) from a certain point (center); a polygon with infinite sides
Circularity
- when on a search, circling back to a previous place visited (definition, web site, etc.), usually unhelpful or redundant
Circumference
- the perimeter of a circle
Clockwise
- in orientation, the direction in which the points are named when, if traveling along the line, the interior of the polygon is on the right (got all that?); see counterclockwise
Coincidental lines
- lines that are identical (one and the same)
Colinear
- in the same line
Compass
- a drawing tool used to draw circles at different radii
Complementary angles
- 2 angles whose measures, when added together, equal 90 degrees; see supplementary angles
Composite transformation
- The composite of a first transformation S and a second transformation T is the transformation mapping a point P onto T(S(P)). When written T2 T1, do T1 first; see translation, rotation, glide reflection, similarity transformation
Concave
- see nonconvex
Concentric circles
- circles that share the same center, but have different radii
Conditional
- a statement that tells if one thing happens, another will follow; written as pq; see antecedent, consequent, converse, inverse, contrapositive
Cone
- the surface of a conic solid whose base is a circle; see right cone
Congruence tranformation
- see isometry
Congruent
- equilateral, equal, exactly the same (size, shape, etc.)
Congruent figures
- two figures where one is the image of the other under a reflection or composite of reflections; written AB
Conic section
- plane section of a cone
Conic solid
- the set of points between a point (the vertex) and a non-coplanar region (the base), including the point and the region; see cone, pyramid, regular pyramid, right cone
Conjecture
- an educated guess or opinion; a hypothesis
Consecutive sides
- sides of a polygon that share an endpoint
Consecutive vertices
- endpoints of a single side of a polygon
Consequent
- the ‘then’ part of a conditional; represented by q; aka conclusion, prove, answer
Constant of an equation
- the term that has no variable in an equation; example: C
Construction
- a precise way of drawing which allows only 2 tools: the straightedge and the compass
Contraction
- a size change where k is less than 1
Contrapositive
- a type of conditional; if not q, then not p; written q p; see inverse
Converse
- a reversed conditional; if a conditional is pq, than its converse is qp
Convex set
- a set of points in which all segments connecting points of the set lie entirely in the set; There are three things one can do to see if a figure is convex – look for “dents”, extend the segments (they shouldn’t enter the figure), and connect any two points within the figure with a segment (if any part of the segment lies outside the figure, it’s concave); see nonconvex set
Coordinate
- a number that identifies (or helps to identify) a point on a number line (or on a plane, or in space)
Coordinate geometry
- the study of geometrically representing ordered pairs of numbers
Coordinate plane
- a plane in which every point is identified with exactly 1 number and vice versa; a two-dimensional graph
Coordinatized line
- a line on which every point is identified with exactly 1 number and vice versa; a one-dimensional graph. The distance between 2 parts on a coordinatized line is the absolute value of the difference of their coordinates.
Coplanar
- within the same plane
Corollary to a theorem
- a theorem that is easily proved from the first
Corresponding angles
- any pair of angles in similar locations with respect to a transversal
Coterminal angles
- two angles that have the same terminal side
Counterclockwise
- in orientation, the direction in which points are named when, if travelling on the line, the interior of the figure is on the left side; see clockwise
Counterexample
- a situation in a conditional for which the antecedent is true, but the conditional is false; aka contradiction
Cylindric solid
- the set of points between a region and its translation in space, including the region and its image
Cylinder
- the surface of a cylindric solid whose base is a circle; see right cylinder
Cylindric surface
- the union of the bases and the lateral surface
Decagon
- a ten-sided polygon
Degree
- unit used to measure angles
Dense line
- the line that contains the shortest path between two points
Diagonal
- a segment in a polygon whose endpoints are 2 nonconsecutive vertices
Diameter of a circle (or sphere)
- the segment whose endpoints are points on a circle (or sphere) that contains the center of the circle as its midpoint; the length of that segment
Dilation
- see size change
Dilatation
- see size change
Dimensions
- the width, length, and height of a plane or space figure
Direction
- the way a number goes – positive or negative
Direction of a translation
- the compass direction in which a translation goes (duh)
Discrete Line
- a line made of dots with space inbetween their centers
Distance
- the distance between points A and B is written as AB
Distance between 2 parallel lines
- the length of a perpendicular segment between them
Dodecagon
- a twelve-sided polygon
Dot
- a description of a point in which the point has a definite size
Duodecagon
- a twelve-sided polygon
Drawing
- a freehand picture using any tool; see construction
Edge
- a segment that helps to make up a face
Empty set
- see null set
Ends of a kite
- the common vertices of the equilateral sides of a kite
Enneagon
- a nine-sided polygon
Equianglular
- having angles of the same measure
Equidistant
- the same distance from something
Equilateral
- equal in length
Equilateral triangle
- a triangle whose sides are equal in length
Even node
- a node that has an even number of arcs
Exclusive or
- one or the other, but not both
Existential statement
- a conditional that uses the word ’same’
Expansion
- a size change where k is greater than 1
Exterior angles
- angles outside of two lines cut by a transversal; see interior angles
Exterior of an angle
- the nonconvex set formed by an angle that measures less than 180 degrees; see interior of an angle
Extremes
- in the proportion , a and d; see means
Face
- a polygonal region of a surface
Family tree
- hierarchy; tower or pyramid of power or importance
Figure
- a set of points
45-45-90 triangle
- an isoscoles right triangle
Fundamental region
- a region used in a tesselation
Geometric mean
- the number g such that for two numbers a and b,
Given
- information assumed to be true in a proof
Glide reflection
- a type of composite transformation where a figure is reflected and then translated in a parallel direction
Goldback’s Conjecture
- if n is an even number greater than 2, then there are always 2 prime numbers whose sum is n
Grade
- the tilt of a real-life object in relation to the horizontal, often used to determine how steep a hill is
Graph theory
- the mathematics of complicated networks
Great circle
- the circle formed by the intersection of a sphere and the plane that contains its center and that divides the sphere into two hemispheres; see small circle
Grid
- a tesselation of congruent squares sometimes used to measure distance
Harmonic mean
- two times the product divided by the sum of the two numbers
Hemisphere
- half of a sphere
Heptagon
- a seven-sided polygon
Hexagon
- a six-sided polygon
Hidden lines
- broken lines used to signify lines that normally wouldn’t be seen in a drawing
Hierarchy
- a chart that shows varying levels of importance
Horizontal line
- a line whose slope is zero
Hypotenuse
- the side opposite the right angle in a right triangle
Icosahedron
- a 20-sided solid; each side is in the shape of a triangle
Identity reflection
- a reflection where the preimage and the image are the same; see reflection symmetry
Identitiy transformation
- a size change where k equals 1
IFF
- if and only if; see biconditional
If-then statement
- see conditional
Image
- the reflection of the preimage
Improper subset
- a subset that includes the entire parent set; see proper subset
Included angle
- the angle made by two sides of a polygon
Included side
- the side between two angles in a polygon
Inclusive or
- one or the other, or both; and/or
Infinite
- uncountable
Initial side
- the side that the measurement of an angle starts from; see terminal side
Instance of a sentence
- a situation where the statement is true
Interior angles
- angles between two lines cut by a transversal; see exterior angles
Interior of an angle
- the convex set formed by an angle that measures less than 180 degrees; see exterior of an angle
Interior of a circle
- the set of points whose distance from the center of the circle is less than that of the radius
Intersecting planes
- planes that share a line
Intersection of two sets A and B
- the set of elements which are in both A and B; written AB
Inverse
- a form of conditional; if not p, then not q; written p q
Irrational number
- decimal number that never ends, never repeats (Ex: pi)
Irregular region
- region whose boundary is not the union of circular arcs or segments
Isometry
- a transformation that keeps the same size and shape of a figure but moves it to a new location; see reflection, rotation, translation, glide reflection
Isoscoles trapezoid
- a trapezoid that has a pair of equiangular base angles
Isoscoles triangle
- a triangle with two sides of equal length
Kite
- a quadrilateral that has two distinct pairs of consecutive equilateral sides
L.A.
- lateral area
Lateral area
- the area of the lateral surface of a solid
Lateral edge
- a segment whose endpoints are corresponding points of a cylindric solid’s bases, or whose endpoints are the vertex of a conic solid and a vertex of its base
Lateral faces
- the faces of the lateral surface of a prism, or a face of a pyramid that is not a base
Lateral surface
- the surface not included in the base(s)
Lattice points
- points in the coordinate plane with integer coordinates
Leg of a right triangle
- a side of a right triangle that include the 90 degree angle
Limit
- the actual area of a region
Line
- a two-dimensional object that has no endpoints and continues on forever in a plane; formed of infinite points; the 3 orientations that lines may have are horizontal, vertical, oblique, and skew lines; written
Linear equation
- Ax + By + C = 0
Linear pair
- 2 supplementary adjacent angles whose noncommon sides form a line
Linear term of an equation
- the term with a variable, but no exponent in an equation; example: By in a linear equation
Line number
- numbers on the left side of a computer screen that tell the computer in what order to do instructions in a computer programming language such as BASIC
Line of reflection
- the line that is reflected over in a reflection
Line perpendicular to a plane
- a line perpendicular to every line in the plane that it intersects (or any one of them)
Lines of sight
- lines from an eye to what it sees that show perspective and what size to draw it
Location
- one of the four main description of a point
Locus
- the set that satisfies a given condition
Magnitude
- the value of a number; its distance from the origin
Magnitude of a rotation
- the amount of rotation in degrees
Magnitude of a translation
- the distance between any point and its image
Major arc
- an arc whose endpoints form an angle over 180 degrees with the center of the circle; written – the extra letter is used to distinguish it from a minor arc; see minor arc
Mapping
- making a transformation
Matrix
- arrangement of pixels
Mean
- average
Meaning
- a version of a conditional that defines a term, where the term is in the antecedent; see sufficient condition
Means
- in the proportion , b and c; see extremes
Measure
- the amount of openness in an angle
Measure of an arc
- The measure of minor arc or major arc is the measure of its central angle.
Median
- the segment connecting the vertex of an angle in a triangle to the midpoint of the side opposite it
Midpoint
- the point M of where AM = AB
Minor arc
- an arc whose endpoints form an angle less than 180 degrees with the center of the circle; written ; see major arc
Net
- a 2-D figure that can be folded on its segments or curved on its boundaries to form a 3-D figure; see article here
Network
- a group of nodes and arcs
N-gon
- a polygon with n sides
Node
- a description of a point in a network where it is possible for two different segments to share the same endpoints
Nonagon
- a nine-sided polygon
Nonconvex set
- a set of points in which not all segments connecting points of the set lie entirely in the set; synonym: concave; see convex set
Non-Euclidean geometry
- solid geometry
Non-included side
- the side of a triangle that is not included by 2 given angles
Non-overlapping regions
- regions that don’t share interior points
Nonperspective drawing
- a three-dimensional drawing that doesn’t use perspective
Null set
- a set with nothing in it
Number line
- a coordinatized line
Oblique prism or cylinder
- a non-right prism or cylinder
Oblique line
- a line that has a definite slope not equal to zero
Obtuse angle
- an angle whose measure is greater than 90 but less than 180 degrees; see acute angle
Octagon
- an eight-sided polygon
Odd node
- a node with an odd number of arcs
One-dimensional
- having length, but no width; examples: a line, a ray, a segment
Opposite faces
- faces that lie in parallel planes
Opposite rays
- two rays with a common endpoint that form a line
Ordered pair
- the two numbers that (called coordinates) are used to identify a point in a plane; written (x, y)
Ordered triple
- the three numbers (called coordinates) that are used to identify a point in space; written (x, y, z)
Orientation
- in an image change, the direction in which the points named go (i.e., how A’s position relates to B’s and B’s relates to C’s); either clockwise or counterclockwise for figures
Overlapping triangles
- triangles that share a side or angle
Parallel lines
- two or more coplanar lines that have no points in common or are identical (eg, the same line)
Parallelogram
- a quadrilateral with both pairs of opposite sides parallel
Parallelpiped
- a prism whose opposite faces are all parallelograms and congruent (in pairs)
Parallel planes
- planes that have no points in common
Pentadecagon
- a 15-sided polygon
Pentagon
- a five-sided polygon
Perimeter of a polygon
- the sum of the lengths of the sides of the polygon
Perpendicular bisector
- the bisector of a segment perpendicular to it
Perpendicular lines
- 2 segments, rays, or lines that form a 90 degree angle
Perpendicular planes
- planes in which any two intersecting lines, one in each plane, form a right angle
Perspective
- feeling of depth
Perspective drawing
- a drawing in which, in order to show perspective, oblique parallel lines will meet
Pi
- written p ( for those of you who can’t read math tags yet); the ratio C/D where C is the circumference and D is the diameter of a circle; 3.14159265359
Pixel
- small dot of color that makes up computer and TV screens
Plane
- a two-dimensional group of points that goes on infinitely in all directions; made up of infinite lines
Plane figure
- a set of points that are on a plane
Plane geometry
- the study of two-dimensional figures in a plane
Plane section
- the intersection of a figure with a plane
Point
- a zero-dimensional figure; while usually left undefined, has four main representions – the dot, the node, the location, and the ordered pair of numbers
Polarity of a variable
- the positivity or negativity of a variable; its direction
Polygon
- a union of 3 or more segments where each segment intersects 2 other segments, one at each endpoint; “many sided”; see reflex polygon
Polygonal region
- the union of a polygon and its interior
Polyhedron
- a three-dimensional surface which is the union of polygonal regions and has no holes
Postulate
- a statement assumed to be true without proof; see theorem
Preimage
- the original object that is reflected
Prism
- the surface of a cylindric solid whose base is a polygon; see right prism, parallelpiped, box
Proof
- a sequence of justified conclusions used to prove the validity of an if-then statement
Proper subset
- a subset that doesn’t include everything in its parent set; see improper subset
Proportion
- a statement that two ratios are equal
Proportional
- one of four numbers that form a true proportion
Protracter
- a tool used to measure angles
Prove
- the goal of a proof
Pyramid
- the surface of a conic solid whose base is a polygon; see regular pyramid
Pythagorean triple
- a set of three numbers that can be side lengths of a right triangle
Q.E.D.
- “quod erat demonstrandum” (Latin) This stems from medieval translators’ habitual tendency of translating the Greek for “this was to be demonstrated” to the Latin phrase above. This appeared originally at the end of many of Euclid’s propositions, signifying that he had proved what he set out to prove.
Q.E.F.
- “quod erat faciendum” is the latin for “which was to be done” It appears in Latin translations of Euclid’s works signifying that he had demonstrated what he had set out to demonstrated.
Quadrangle
- a four-sided polygon; see quadrilateral
Quadratic equation
- Ax2 + By + C = 0
Quadratic term of an equation
- the term Ax2 in a quadratic equation
Quadrilateral
- a four-sided polygon; see rhombus, parallelogram, square, rectangle, trapezoid, isoscoles trapezoid, kite
R
- rotation
r
- radius
Radii
- plural form of radius
Radius
- the segment whose endpoints are any point on a circle or sphere and its center; the length of that segment
Rate
- a ratio where the quantities are of different kinds; example: 60 miles per hour
Ratio
- a quotient of 2 numbers
Ratio of similtude
- the ratio of the length of an image to the length of the preimage
Ray
- a one-dimensional figure that consists of one endpoint A, one point B, all of the points on , and all points for which B is between them and A; written
Rectangle
- a quadrilateral whose angles are all right angles
Rectangular solid
- the union of a box and its interior
Reference angle
- the angle of less than 360 degrees that corresponds to an angle of over 360 degrees; In order to get the reference angle, you must subtract 360 degrees from the given angle until there is less than 360 degrees left.
Refine
- to change a conjecture slightly so that it is true
Reflecting line
- see line of reflection
Reflection image
- For a point A not on the reflecting line, its reflection image is the point B where the reflecting line is the perpendicular bisector of . For a point A on the reflecting line, its reflection image is itself.
Reflection image of a figure
- the set of all of the reflection images of points in the figure
Reflection notation
- rm(ABC), which stands for the reflection over line m of figure ABC
Reflection-symmetric figure
- a figure that shows reflection symmetry
Reflection symmetry
- a characteristic of a figure in which there is a reflection line where its reflection is itself
Reflex polygon
- a polygon for which 2 or more of its sides intersect each other
Region
- the union of a figure and its interior
Regular polygon
- a convex polygon whose angles and sides are all congruent
Regular pyramid
- a pyramid whose base is a regular polygon and whose vertex forms a segment with the center of the polygon perpendicular to its plane
Resolution
- the density of pixels in a picture
Rhombus
- a parallelogram with four equilateral sides
Right angle
- an angle whose measure is 90 degrees
Right cone
- a cone whose axis is perpendicular to the plane containing its base
Right cylinder
- a cylinder whose direction of sliding is perpendicular to the plane of the base
Right prism
- a prism whose direction of sliding is perpendicular to the plane of the base
Right triangle
- a triangle that has a 90 degree angle
Rotation
- the composite of two reflections over intersecting lines
S.A.
- surface area
Scale factor
- size change magnitude
Scalene triangle
- a triangle with no equilateral sides
Secant to a circle
- a line that intersects the circle in two points
Sector
- part of a circle containing its center and an arc
Segment
- aka line segment; the set of points consisting of two distinct points and all inbetween them; written
Semicircle
- an arc whose central angle is a right angle
Septagon
- a seven-sided polygon
Set
- a collection of objects called elements
Side of a polygon
- a single segment from the union that forms a polygon
Similar figures
- two figures that have a similarity transformation mapping one onto the other; written F G
Similarity transformation
- a transformation that is the composite of size changes and/or reflections
Size change
- Let A be a point and k be a positive real number. For any point B, let T(B) = B’ be the point on with OP’ = K*OP. Then S is the size change with center A and magnitude k. See transformation.
Size change factor
- size change magnitude
Size transformation
- see size change
Skew lines
- non-coplanar lines that don’t intersect
Slant height
- the length of a lateral edge of a conic solid
Slide
- see translation
Slope
- the measure of the tilt of a line; rise over run (i.e., how much the line moves up for every movement to the right). The formula for slope is
y2-y1
x2-x1
Small circle
- the circle formed by the intersection of a sphere and a plane that doesn’t contain the center
Solid
- the union of the surface and the region of space enclosed by a 3-D figure; examples: conic solid, cylindric solid, rectangular solid
Solid geometry
- the study of figures in three-dimensional space
Space
- the set of all possible points; made up of infinite planes
Sphere
- the set of points in space equidistant from a certain point
Square
- an equilateral and equianglular quadrilateral
Straight angle
- an angle whose measure is 180 degrees, forming a line with its sides
Straightedge, unmarked
- just how it sounds, an unmarked tool used to draw straight lines
Subroutine
- a previously known algorithm used in another algorithm
Subset
- a set that is part of a larger set
Sufficient condition
- a version of a conditional that tells you when you can use the term defined, where the term is in the consequent; a condition that implies a preset conclusion; see meaning
Supplementary angles
- 2 angles whose measures, when added together, equal 180 degrees
Surface
- the boundary of a 3-D figure
Surface area
- the total area of the surface of a solid
Symmetry diagonal
- the diagonal that perpendicularly bisects the other and is a symmetry line for the kite
Symmetry line
- the line of reflection in a reflection-symmetric figure
Terminal side
- the side that the measurement of an angle ends at
Tesselate
- the ability of a region to tessalate
Tesselation
- a covering of a plane with congruent copies of the same region with no holes or overlaps
Tetragon
- a four-sided polygon; see quadrilateral
Theorem
- important mathematical statements which can be proven by postulates, definitions, and/or previously proved theorems
Three-dimensional
- having length, width, and thickness (i.e., space)
3-D figure
- a set of points in space; examples: box, cone, cylinder, parallelpiped, prism, pyramid, regular pyramid, right cone, right cylinder, right prism, sphere,
Tilt
- the measure of an angle as compared to a horizontal line; what happens when you kick the pinball machine too hard; see grade
Torus
- a 3-D figure formed by rolling a rectangle into a cylinder and bending the cylinder until its bases meet; a “doughnut”; see net
Transformation
- a correspondence between two sets of points such that each point in the preimage has a unique image and that each point in the image has exactly one preimage; see reflection, size change, isometry, composite
Transformation notation
- T(P), which stands for the transformation of P; also Sk where the transformation S that maps (x, y) onto (kx, ky) and k is the magnitude of that transformation
Translation
- the composite of two reflections over parallel lines; aka slide
Transversal
- a line that intersects 2 others
Transversible
- a network in which all arcs can be traced without going over one more than once
Trapezoid
- a quadrilateral that has at least one pair of parallel sides; see isoscoles trapezoid
Triangle
- a polygon with three sides; see equilateral triangle, isoscoles triangle, right triangle, scalene triangle
Triangulate
- to divide a polygon into triangles
Tridecagon
- a 13-sided polygon
Trigon
- a three-sided polygon; see triangle
Two-dimensional
- having both width and length, but no thickness
Undecagon
- an eleven-sided polygon
Union of two sets A and B
- the set of elements in A, B, or both; written AUB
Unit cube
- unit of measuring volume
Universal statement
- a conditional that uses the words ‘all’ or ‘everything’
Universe
- in a Venn diagram, everything that is outside the sets
Vanishing line
- the horizon; in a drawing it is at the height of viewer’s eye
Vanishing point
- the point in space where two parallel lines seem to meet
Vertex
- see node
Vertex angle
- the angle formed by the equilateral sides of an isoscoles triangle
Vertex of an angle
- the common endpoint of the two rays
Vertex of a conic solid
- the point that marks the thinnest part of a conic solid
Vertex of a polygon
- an endpoint of a segment in a polygon
Vertical angles
- 2 angles that share a common vertex and whose sides form 2 lines
Vertical line
- a line that goes straight up and down, and whose slope is defined as infinite or undefined
View
- a drawing of a side of an object
Volume
- the amount of space a 3-D object can hold
Wedge
- see sector
Zero angle
- an angle whose measure is 0. In a zero angle, both the initial and terminal sides are the same.
Zero-dimensional
- having no dimension; a point