garment bag vs travelling bag

garment bag and travelling bag both are nouns.

Word	Noun	Adjective	Verb	Adverb
garment bag	Yes	No	No	No
travelling bag	Yes	No	No	No

As nouns, travelling bag is a hypernym of garment bag; that is, travelling bag is a word with a broader meaning than garment bag:

Other hypernyms of garment bag include bag, grip, suitcase, traveling bag.

garment bag (noun)	travelling bag (noun)
a suitcase that unfolds to be hung up	a portable rectangular container for carrying clothes