Trigonometric function
'trigonometric function' is the definition.
(sine is a kind of trigonometric function)
This is all the clue.
(Other definitions for sine that I've seen before include "Mathematical function" , "Trigonometric function" , "Opposite/hypoteneuse" , "Trigonometrical function" , "Indefinitely, with no appointed date - . . . . die" .)
'trigonometric function' is the definition.
(tangent is a kind of trigonometric function)
This is the entire clue.
(Other definitions for tangent that I've seen before include "Particular line" , "Straight line touching a circle" , "mathematician's line" , "Line that touches curve without crossing it" , "Straight line that touches but does not intersect a curve" .)