# Definition:Tangent Plane

## Definition

Let $S$ be the surface of a solid geometric figure.

Let $Q$ be a point on $S$.

A tangent plane to $S$ at $Q$ is a plane $P$ which intersects $S$ such that:

all straight lines $\LL$ embedded in $P$ that intersect $S$ are tangent to $S$.

## Also see

• Results about tangent planes can be found here.