\begin{definition}[Definition:Directed Line Segment]
A '''directed line segment''' is a line segment endowed with the additional property of direction.
It is often used in the context of applied mathematics to represent a vector quantity.
{{expand|Perhaps the above statement should also be expanded to allow a D.L.S. to be defined as a '''vector quantity''' applied at a particular point. There is a danger (as pointed out on the Definition:Vector Quantity page) of implying  / believing that a vector, in general, is applied at a particular point, for example usually the origin. Thus, this page allows the opportunity to consider a definition of an object which consists of a vector "rooted" at a particular point, as a convenient fiction for what is actually happening in the context of physics.}}
{{stub|needs a picture
It may be worthwhile to point out that this can be formalized with an ordered pair.
Establish connection with Definition:Affine Space}}
\end{definition}