Trigonometric Functions: The fundamental trigonometric functions, including sine, cosine, and tangent, which describe the relationships between the sides and angles of a right triangle.
Inverse Trigonometric Functions: The inverse functions of the trigonometric functions, such as arcsin, arccos, and arctan, which allow you to find the angle given the value of a trigonometric function.
Angle Measure: The representation of an angle, typically in radians or degrees, which describes the amount of rotation around a fixed point.