trigonometric function
n.
A function of an angle expressed as the ratio of two of the sides of a right triangle that contains that angle; the sine, cosine, tangent, cotangent, secant, or cosecant. Also called circular function.
trigonometric functionIn a right triangle, the three main trigonometric functions are
sine θ = opposite / hypotenuse
cosine θ = adjacent / hypotenuse
tangent θ = opposite / adjacent.