organ pipe vs flue pipe

organ pipe and flue pipe both are nouns.

Word	Noun	Adjective	Verb	Adverb
organ pipe	Yes	No	No	No
flue pipe	Yes	No	No	No

As nouns, flue pipe is a hyponym of organ pipe; that is, flue pipe is a word with a more specific, narrower meaning than organ pipe:

organ pipe: the flues and stops on a pipe organ
flue pipe: organ pipe whose tone is produced by air passing across the sharp edge of a fissure or lip

Other hyponyms of organ pipe include flue, labial pipe, organ stop, reed pipe.

organ pipe (noun)	flue pipe (noun)
the flues and stops on a pipe organ	organ pipe whose tone is produced by air passing across the sharp edge of a fissure or lip