light beam vs sunray

light beam and sunray both are nouns.

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

As nouns, sunray is a hyponym of light beam; that is, sunray 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, moonbeam, sunbeam, laser beam, low beam.

light beam (noun)	sunray (noun)
a column of light (as from a beacon)	a ray of sunlight
	a ray of artificial ultraviolet light from a sunray lamp
	herb having a basal cluster of grey-green leaves and leafless stalks each with a solitary broad yellow flower head; desert areas Idaho to Arizona