tap-hole
(ˈtæphəʊl)
[f. tap n.1 + hole n.]
1. The hole in a cask, vat, or the like, in which the tap is inserted.
| 1594 Plat Jewell-ho. iii. 10 These halfe tubs hauing tap-holes within. 1707 Mortimer Husb. (1721) II. 322 Put it back again, stopping your Tap-hole. |
2. A small opening in a furnace, through which the metal, or slag, or both, may be run out; also, a hole in a cementation furnace in which tap-bars (see tap n.1 8) are inserted.
| 1825 J. Nicholson Operat. Mechanic 341 Each pot has also small openings in its end, through which the ends of two or three of the bars are left projecting in such a manner, that by only removing one loose brick from the external building, the bars can be drawn out..; these are called the tap-holes. 1839 Ure Dict. Arts 320 In the melting furnaces, the metal is run out by a tap-hole in the side. 1861 Fairbairn Iron 101 The fluid iron, as it flows from the tap-hole, is fully white hot, and perfectly limpid. |