Tap, n. [AS. tæppa, akin to D. tap, G. zapfen, OHG. zapfo, Dan. tap, Sw. tapp, Icel. tappi. Cf. Tampion, Tip.] 1. A hole or pipe through which liquor is drawn.
2. A plug or spile for stopping a hole pierced in a cask, or the like; a faucet.
3. Liquor drawn through a tap; hence, a certain kind or quality of liquor; as, a liquor of the same tap.
4. A place where liquor is drawn for drinking; a taproom; a bar.
5. (Mech.) A tool for forming an internal screw, as in a nut, consisting of a hardened steel male screw grooved longitudinally so as to have cutting edges.
On tap. (a) Ready to be drawn; as, ale on tap. (b) Broached, or furnished with a tap; as, a barrel on tap. — Plug tap(Mech.), a screw-cutting tap with a slightly tapering end. — Tap bolt, a bolt with a head on one end and a thread on the other end, to be screwed into some fixed part, instead of passing through the part and receiving a nut. See Illust. under Bolt. — Tap cinder(Metal.), the slag of a puddling furnace.