light beam vs high beam

light beam and high beam both are nouns.

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

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

light beam: a column of light (as from a beacon)
high beam: the beam of a car's headlights that provides distant illumination

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

light beam (noun)	high beam (noun)
a column of light (as from a beacon)	the beam of a car's headlights that provides distant illumination