Sine Function: The sine function (sin(x)) represents the ratio between the length of the side opposite an angle in a right triangle and its hypotenuse.
Trigonometric Functions: Trigonometric functions include sine, cosine, tangent, cotangent, secant, and cosecant. They relate the angles of a right triangle to the ratios of its sides.
Unit Circle: A unit circle is a circle with a radius of 1 unit centered at the origin (0,0) on a coordinate plane. It is commonly used to understand trigonometric functions and their values for different angles.