[ 'tan(d)ʒ(ə)nt ]
■ noun
1》 a straight line or plane that touches a curve or curved surface at a point, but if extended does not cross it at that point.
2》 Mathematics the trigonometric function that is equal to the ratio of the sides (other than the hypotenuse) opposite and adjacent to an angle in a right-angled triangle.
3》 a completely different line of thought or action: my mind went off at a ~.
■ adjective (of a line or plane) touching, but not intersecting, a curve or curved surface.
Derivatives
tangency noun
Origin
C16: from L. ~- , tangere 'touch'.