pouch vs belt bag

pouch and belt bag both are nouns.

Word	Noun	Adjective	Verb	Adverb
pouch	Yes	No	Yes	No
belt bag	Yes	No	No	No

As nouns, belt bag is a hyponym of pouch; that is, belt bag is a word with a more specific, narrower meaning than pouch:

pouch: a small or medium size container for holding or carrying things
belt bag: a small pouch (usually with a zipper) that attaches to a belt and is worn around the waist

Other hyponyms of pouch include mail pouch, mailbag, pocket, sporran, tobacco pouch, waist pack.

pouch (noun)	belt bag (noun)
a small or medium size container for holding or carrying things	a small pouch (usually with a zipper) that attaches to a belt and is worn around the waist
(anatomy) saclike structure in any of various animals (as a marsupial or gopher or pelican)
an enclosed space

pouch (verb)	belt bag (verb)
swell or protrude outwards
put into a small bag
send by special mail that goes through diplomatic channels