portmanteau vs travelling bag

portmanteau and travelling bag both are nouns.

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

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

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

portmanteau (noun)	travelling bag (noun)
a large travelling bag made of stiff leather	a portable rectangular container for carrying clothes
a new word formed by joining two others and combining their meanings