# Definition:Line/Straight Line

< Definition:Line(Redirected from Definition:Straight Line)

## Definition

In the words of Euclid:

*A***straight line**is a line which lies evenly with the points on itself.

(*The Elements*: Book $\text{I}$: Definition $4$)

## Also see

An alternative definition for **straight line** which is frequently encountered is:

This is all very well but it assumes that the line in question terminates at two particular endpoints.

However, this is a perfectly valid definition of the concept of a **straight line segment**.