The equation \sec(\theta) = \frac1\cos(\theta) defines the secant function in trigonometry. Here, \theta represents an angle, and \cos(\theta) is the cosine of that angle. The secant function is the reciprocal of the cosine function, meaning that wherever the cosine value is non-zero, the secant can be calculated. In a right triangle, the cosine of an angle is the ratio of the length of the adjacent side to the hypotenuse. Therefore, the secant function can also be understood as the ratio of the hypotenuse to the length of the adjacent side, providing a different perspective on the relationship between these sides in a triangle.