切点的英文：
point of tangency
tangent point

Cut yourself some pineapple.
你自己切点菠萝吃吧.

That is not the point in question.
那不是要考虑的要点。

orientation point
方位点

A score made on a try for a point or points after a touchdown.
触地得分在触地后再次发球所得的一分或几分

The direction is tangent to the trajectory.
方向就是轨道的切线方向。

The tangent is a relatively important concept in trigonometry.

The graph of a concave function is always below its tangent.
一个凹函数的图象总在它的切线的下方。