noun
: any of a set of six functions analogous to the trigonometric functions but related to the hyperbola in a way similar to that in which trigonometric functions are related to a circle
noun
: any of a set of six functions analogous to the trigonometric functions but related to the hyperbola in a way similar to that in which trigonometric functions are related to a circle
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012