light beam vs moonbeam

light beam and moonbeam both are nouns.

Word	Noun	Adjective	Verb	Adverb
light beam	Yes	No	No	No
moonbeam	Yes	No	No	No

As nouns, moonbeam is a hyponym of light beam; that is, moonbeam is a word with a more specific, narrower meaning than light beam:

Other hyponyms of light beam include heat ray, high beam, moon-ray, moon ray, sunbeam, sunray, laser beam, low beam.

light beam (noun)	moonbeam (noun)
a column of light (as from a beacon)	a ray of moonlight