Noun
The quality or state of being tangent; a contact or touching.
Source: Webster's dictionaryAs it passes through the point where the tangent line and the curve meet, called the point of tangency, the tangent line is "going in the same direction" as the curve, and is thus the best straight-line approximation to the curve at that point. Source: Internet
The extouch triangle of a reference triangle has its vertices at the points of tangency of the reference triangle's excircles with its sides (not extended). Source: Internet
In the field of computer graphics, these three levels are sometimes called G 0 (continuity of position), G 1 (continuity of tangency), and G 2 (continuity of curvature). Source: Internet
Normal line to a curve The line perpendicular to the tangent line to a curve at the point of tangency is called the normal line to the curve at that point. Source: Internet