Acute Angle: An angle that measures less than 90 degrees.
Adjacent Angles: Two angles that have a common vertex and a common side, but do not overlap.
Complementary Angles: Two angles whose measures add up to 90 degrees.
Obtuse Angle: An angle that measures more than 90 degrees but less than 180 degrees.
Right Angle: An angle that measures exactly 90 degrees.
Supplementary Angles: Two angles whose measures add up to 180 degrees.
Vertical Angles: A pair of non-adjacent angles formed by two intersecting lines.