comb vs pocket comb

comb and pocket comb both are nouns.

Word	Noun	Adjective	Verb	Adverb
comb	Yes	No	Yes	No
pocket comb	Yes	No	No	No

As nouns, pocket comb is a hyponym of comb; that is, pocket comb is a word with a more specific, narrower meaning than comb:

comb: a flat device with narrow pointed teeth on one edge; disentangles or arranges hair
pocket comb: a small comb suitable for carrying in a pocket

Other hyponyms of comb include currycomb, fine-tooth comb, fine-toothed comb, pocketcomb, dematting comb.

comb (noun)	pocket comb (noun)
the act of drawing a comb through hair	a small comb suitable for carrying in a pocket
ciliated comb-like swimming plate of a ctenophore
the fleshy red crest on the head of the domestic fowl and other gallinaceous birds
a flat device with narrow pointed teeth on one edge; disentangles or arranges hair
any of several tools for straightening fibers

comb (verb)	pocket comb (verb)
smoothen and neaten with or as with a comb
search thoroughly
straighten with a comb