Basic Geometric Terms

Front 1

Point

Back 1

Undefined term, specific location. Has no dimension and is represented by a dot

Front 2

Line

Back 2

Undefined term, connected straight path. No thickness and extends forever in both directions

Front 3

Plane

Back 3

Undefined term, flat surface. No thickness and extends forever in all directions

Front 4

Line segment

Back 4

Portion of line consisting of 2 points and all points in between them

Front 5

Ray

Back 5

Portion of line that starts at one point and continues forever in one direction

Front 6

Collinear

Back 6

Points that lie on the same line

Front 7

Noncollinear

Back 7

3 or more points that don't lie on the same line

Front 8

Coplanar

Back 8

Points or lines that lie on the same plane

Front 9

Noncoplanar

Back 9

Points or lines that don't lie on the same plane

Front 10

Parallel

Back 10

Lines in same plane that don't intersect

Front 11

Skew

Back 11

Lines that are not coplanar and don't intersect

Front 12

Congruent

Back 12

2 segments that have the same length

Front 13

Opposite rays

Back 13

2 rays that have a common endpoint to form a line

Front 14

Segment bisector

Back 14

Line, ray or segment divides a segment in 2 congruent segments

Front 15

Space

Back 15

Set of all points in 3 dimensions

Front 16

Thru any 2 points, there is exactly

Back 16

One line

Front 17

If 2 lines intersect

Back 17

They form exactly one point

Front 18

Thru any 3 noncollinear points, there is exactly

Back 18

One plane

Front 19

If 2 lines intersect they form exactly

Back 19

One line

Front 20

A line and point are ___ coplanar

Back 20

Always

Front 21

2 segments are ___ coplanar

Back 21

Sometimes

Front 22

2 points are ___ collinear

Back 22

Always

Front 23

2 planes ___ intersect on one point

Back 23

Never

Front 24

A plane containing 2 points of a line ___ contains the entire line

Back 24

Always

Front 25

Intersecting lines are ___ coplanar

Back 25

Always

Front 26

3 points are ___ coplanar

Back 26

Always