There are six basic trigonometric functions that can be used to interpret the measurement of angles and triangles—most often defined as circle trig definitions. In terms of the illustration below, the following lists the six trig functions of θ, all defined in terms of the coordinates of Q (x, y):

The full names for these functions are cos (cosine); sin (also seen as “sine”); tan (tangent); sec (secant); csc (cosecant); and cot (cotangent).