A pipe through which the blast is delivered to the interior of a blast furnace, or to the fire of a forge; a tuyere.
Origin
From Middle English twiren, cognate with Middle High German zwieren, Bavarian zwiren, zwieren. Perhaps related to Old English twinclian. More at twinkle.
From Middle English *twir, *twirn, twern, from Old English *twirn, *tweorn, from Proto-West Germanic *twiʀn, from Proto-Indo-European *duwo-. twine.
Perhaps from a dialectal form of *twere, from Middle English *tweren, from Old English þweran (found in compound āþweran), from Proto-Germanic *þweraną, from Proto-Indo-European *twer-. Cognate with Bavarian zweren. Compare twirk, twirl.