n.[C]

1. 【数】正切；切线
2. （铁路或道路的）直线区间

a.

1. 【数】正切的；相切的；切线的
   tangent circles

   相切的圆

2. 离题的；背离原来途径的
   tangent remarks

   离题的话

n.

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 tangent.

adj.