The direction of the path in which light is traveling is called a ray and is represented in diagrams by a straight line with an arrow on it.
A beam, however, is a stream of light and is shown by a number of rays; it may be parallel, diverging (spreading out) or converging (getting narrower).
There are several ways of describing light, some more useful in certain circumstances.
We can think of light as a beam or ray, as a wave front or series of crests, as a single waves or as a stream of photons (4 methods to my knowledge) and each has their own area where they are more applicable. No one view is right or wrong, just more or less useful to describe the phenomena we're looking at.