1) This refers to a nozzle through which a blast of air is forced into a forge or furnace.
It derives from the French word which gave modern tuy?re, and early OED spellings include tewer, tuer, twyer and tewyre. The reference in 1350-1 to 'ij tuers ferri' makes it clear that the nozzle could be of iron, and popular etymology was responsible for ‘tew-iron’ and similar spellings. That was almost predictable, given that ‘ire’ was a regional alternative to iron, n.b. 1343 Roger le Irmongere. The development may have taken place in the sixteenth century and the OED notes it in Durham in 1570 when a smith gave vnto John Dycheborne a pair of bellowis with a tewe Ireon. The earliest West Riding example is in the will of a blacksmith named Robert Saureby: 1558 a stithy, a cantell of yron and a tewyron, Sheffield. In 1592, an Eckington smith called Richard Gill had two tew irons in his smithy and in 1692, Anne Harrison, a Sheffield widow, had 1 pair of bellowes tue irons and 1 double bellow, valued at Ł1. 1s. The inventory of Godfrey Creswick, a Sheffield cutler, listed A pair of Bellows and a Tuiron in 1704. Closer to the original French word is the plural spelling Turiors listed in 1608 among implements in a Cawthorne smithy, possibly at Cinderhill.