tangent

A straight line touching a curve at a single point without crossing it there.

A function of an angle that gives the ratio of the sine to the cosine, in either the real or complex numbers. Symbols: tan, tg.

A topic nearly unrelated to the main topic, but having a point in common with it.

“I believe we went off onto a tangent when we started talking about monkeys on unicycles at his retirement party.”

A small metal blade in a clavichord that strikes the strings to produce sound.

Touching a curve at a single point but not crossing it at that point.

Of a topic, only loosely related to a main topic.