water pipe vs tobacco pipe

water pipe and tobacco pipe both are nouns.

Word	Noun	Adjective	Verb	Adverb
water pipe	Yes	No	No	No
tobacco pipe	Yes	No	No	No

As nouns, tobacco pipe is a hypernym of water pipe; that is, tobacco pipe is a word with a broader meaning than water pipe:

water pipe: an oriental tobacco pipe with a long flexible tube connected to a container where the smoke is cooled by passing through water
tobacco pipe: a tube with a small bowl at one end; used for smoking tobacco

Other hypernyms of water pipe include pipe.

water pipe (noun)	tobacco pipe (noun)
an oriental tobacco pipe with a long flexible tube connected to a container where the smoke is cooled by passing through water	a tube with a small bowl at one end; used for smoking tobacco