irradiation vs low beam

irradiation and low beam both are nouns.

Word	Noun	Adjective	Verb	Adverb
irradiation	Yes	No	No	No
low beam	Yes	No	No	No

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

irradiation: a column of light (as from a beacon)
low beam: the beam of a car's headlights that provides illumination for a short distance

Other hyponyms of irradiation include heat ray, high beam, moon-ray, moon ray, moonbeam, sunbeam, sunray, laser beam.

irradiation (noun)	low beam (noun)
(medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance	the beam of a car's headlights that provides illumination for a short distance
the apparent enlargement of a bright object when viewed against a dark background
(Pavolvian conditioning) the elicitation of a conditioned response by stimulation similar but not identical to the original stimulus
(physiology) the spread of sensory neural impulses in the cortex
a column of light (as from a beacon)
the condition of being exposed to radiation