air-raid shelter vs bomb shelter

air-raid shelter and bomb shelter both are nouns.

Word	Noun	Adjective	Verb	Adverb
air-raid shelter	Yes	No	No	No
bomb shelter	Yes	No	No	No

As nouns, air-raid shelter and bomb shelter are synonyms defined as:

air-raid shelter and bomb shelter: a chamber (often underground) reinforced against bombing and provided with food and living facilities; used during air raids

Other synonyms of air-raid shelter include bombproof.

air-raid shelter (noun)	bomb shelter (noun)
a chamber (often underground) reinforced against bombing and provided with food and living facilities; used during air raids	a chamber (often underground) reinforced against bombing and provided with food and living facilities; used during air raids