**
Colinear
** -
Lying in one line (usually refers to a set of points).

**
Congruent
** -
Of exactly the same size and shape; in other words, of exactly the same
dimensions.

**
Coplanar
** -
Existing in one plane (usually refers to points or lines).

**
Dimension
** -
The number of lines required to span a region in space.

**
Line
** -
A collection of points arrayed in a straight formation without limit.

**
Noncolinear
** -
Not lying in one line (usually refers to a set of points).

**
Noncoplanar
** -
Not existing in one plane (usually refers to points or lines).

**
Perpendicular
** -
At a 90 degree angle (something is
perpendicular relative to something else).

**
Plane
** -
A flat, boundless surface in space.

**
Point
** -
A specific location in space.

**
Ray
** -
A portion of a line with a fixed endpoint on one end that extends without
bound in the other direction.

**
Segment
** -
A portion of a line with two endpoints and, thus, finite length.

**
Space
** -
The collection of all points.