An angle is a measure of rotation between two intersecting lines or surfaces. It quantifies the amount of turning or bending occurring at that point.
Radian: Radian is a unit used for measuring angles derived from comparing arc lengths to radii on circles. It does not have any units.
Degree: Degree is another unit used for measuring angles, where one full circle consists of 360 degrees.
Right Angle: A right angle measures exactly 90 degrees and forms an "L" shape when two perpendicular lines intersect.