A line segment refers to a straight and limited portion of a line that has two endpoints and a measurable length.

It includes all the points that lie between these endpoints and has a measurable length. A line segment is usually represented by the bar symbol (—) on top of the endpoints.

Explanation: In this image , line segment has endpoints A and it can be denoted by the \$\bar(AB)\$

A ray is a part of a line that has one endpoint (i.e., starting point), and it extends in one direction endlessly.

A ray has an unlimited length, unlike a line segment.

Explanation:

"P" is the origin of the ray, while "Q" is the point it passes through. The direction of travel is shown by an arrow above the points as \$\overrightarrow(PQ)\$.