Meaning

noun flat bladelike projection on the arm of an anchor

noun organ pipe whose tone is produced by air passing across the sharp edge of a fissure or lip

noun a conduit to carry off smoke

originFrom Middle English flue, flewe (“mouthpiece of a hunting horn”), of uncertain origin. Perhaps a back-formation from Middle English *flews (mistaken as a plural), from Old English flēwsa (“a flow, flowing, flux”). Alternatively, perhaps an alteration of Middle English floute, fleute, flote (“a pipe”), see English flute. Compare also Middle Dutch vloegh (“groove, channel, flute of a fluted…

Etymology from Wiktionary, CC BY-SA 3.0