# Line and Line Segment ## Line A **line** in the plane is a non-empty set of points with the property that there is a [[vector]], say $\vec{a}$, with the property that for any two points, say $P$ and $Q$, on the line then the position vector $\vec{P Q}$ is [[parallel vector|parallel]] to $\vec{a}$. ## Line Segment A **line segment** is a section of a line with the property that if $P$ and $Q$ are on the line then every point between $P$ and $Q$ on the line is also in the line segment. [[!redirects line segment]] [[!redirects line segments]] [[!redirects lines]]