ice bag vs ice pack

ice bag and ice pack both are nouns.

Word	Noun	Adjective	Verb	Adverb
ice bag	Yes	No	No	No
ice pack	Yes	No	No	No

As nouns, ice bag and ice pack are synonyms defined as:

ice bag and ice pack: a waterproof bag filled with ice: applied to the body (especially the head) to cool or reduce swelling

ice bag (noun)	ice pack (noun)
a waterproof bag filled with ice: applied to the body (especially the head) to cool or reduce swelling	a waterproof bag filled with ice: applied to the body (especially the head) to cool or reduce swelling
	a large expanse of floating ice