- noun a trigonometric function equal to the length of the side opposite the angle of a right-angled triangle divided by the length of the adjacent side
- noun a straight line, curve or surface which meets another curve or curved surface at a point, but which, if extended, does not cut through at that point
- A straight line or curve that touches another curve at a single point without crossing the curve.
- For a right triangle, the ratio of the length of the side opposite to an acute angle, to the length of the side adjacent to said acute angle. It is the same as the ratio of the sine to the cosine. Its abbreviation is tan.
- A line, curve, or plane which touches another curve or surface at a single point, but does not intersect it.