noun Date: circa 1890 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 the trigonometric functions are related to a circle
HYPERBOLIC FUNCTION
Meaning of HYPERBOLIC FUNCTION in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012