How many endpoints does a ray have?

A ray has many points, but it has only one endpoint. The rest of the points extend away from the endpoint infinitely along a linear path.

This is different than a line segment, which has two endpoints between which a finite distance can be measured. A ray's length is infinite, but only in 1 direction away from its endpoint.

A sunbeam can be thought of as a ray. The sun is like the endpoint. Each beam of light begins at the sun and radiates away from it in one direction. Some of the sun's rays point in a path toward Earth. Other rays point in different directions, either passing by us, or going in a direction away from us.