- Of a topic, only loosely related to a main topic.
- (geometry) Touching a curve at a single point but not crossing it at that point.
- (geometry) A straight line touching a curve at a single point without crossing it there.
- A small metal blade by which a clavichord produces sound.
- 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."
- (trigonometry) In a right triangle, the ratio of the length of the side opposite the angle to the length of the side adjacent to the angle. Symbols: tan, tg