Geometry Terminology

Starting Place

100

An infinite length of points

Line

200

A location in space

Point

300

Points where a line segment ends

endpoints

400

The point of an angle where two rays meet

Vertex

500

A line that starts at a point and extends infinitely

Ray

Product of Lines

100

Part of a line

Line Segments

200

Flat Surface

Plane

300

Lines on the same plane

Coplanar Lines

400

The point where two or more lines cross

Intersection 

500

Lines that are not in the same plane

Skew Lines

Angles

100

Angles measure less than 90^o

Acute Angles

200

Angles that measure 90^o

Right Angles

300

Angles between 90^o and 180^o

Obtuse Angles

400

Angle that are exactly 180^o

Straight Angles

500

Angles that have a common vertex, Across from each other, and do not have the same side

Vertical Angles

Geometry Misc.

100

Same Size, shape and measure

Congruent

200

Line segments with the same lengths

Congruent line segment

300

Divide into two equal parts

Bisect

400

When two lines intersect at 90^o angles

Perpendicular

500

Part of a circle, the curve between two points

Arc

More Angles

100

Two angles that have the same measure

Congruent Angles

200

Cut an angle int two equal parts

Angle Bisector

300

The Sum of angle is 180^o

Supplementary Angles

400

Sum of the angles is 90^o

Complementary Angles

500

Angles that share a common vertex and side

Adjacent Angles