Alternate exterior angles
Exterior angles on alternate sides of the transversal (not on the same parallel line)

Alternate interior angles
Interior angles on alternate sides of the transversal (not on the same parallel line)

Complementary angles
Two positive angles that when added give 90 degrees.

Corresponding angles
Any pair of angles in similar locations with respect to a transversal

Parallel lines
Two lines in the same plane that never cross or intersect.

Perpendicular lines
Two segments, rays, or lines that form a 90 degree angle.

Supplementary angles
Two angles whose measures, when added together, equal 180 degrees.

Transversal
A line that intersects  others.

Vertical angles
Two angles that share a common vertex and whose sides form two straight lines.