irradiation vs sunbeam

irradiation and sunbeam both are nouns.

Word	Noun	Adjective	Verb	Adverb
irradiation	Yes	No	No	No
sunbeam	Yes	No	No	No

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

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

irradiation (noun)	sunbeam (noun)
(medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance	a ray of sunlight
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