Line Segment

A segment, or line segment, is part of a line bounded by two different points, called endpoints. It is made of all the points on the line between the endpoints. Unlike a line, a segment does not extend infinitely, and then it is drawn without arrowheads.

As with a line, between two different points there is exactly one segment. A segment with endpoints A and B is denoted as AB or BA while its length or measure is written as AB or BA. When two segments have the same length they are said to be congruent.