tapv. t.[F. taper to strike; of Teutonic origin; cf. dial. G. tapp, tapps, a blow, tappe a paw, fist, G. tappen to grope.]1. To strike with a slight or gentle blow; to touch gently; to rap lightly; to pat; as, to tap one with the hand or a cane.()2. To put a new sole or heel on; as, to tap shoes.()n.[Cf. F. tape. See Tap to strike.]1. A gentle or slight blow; a light rap; a pat.(Addison.)2. A piece of leather fastened upon the bottom of a boot or shoe in repairing or renewing the sole or heel.()3. (Mil.) A signal, by drum or trumpet, for extinguishing all lights in soldiers' quarters and retiring to bed, -- usually given about a quarter of an hour after tattoo.(Wilhelm.)v. i. To strike a gentle blow.()n.[AS. tppa, 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.()v. t.1. To pierce so as to let out, or draw off, a fluid; as, to tap a cask, a tree, a tumor, a keg of beer, etc.()2. Hence, to draw resources from (a reservoir) in any analogous way; as, to tap someone's knowledge of the Unix system; to tap the treasury.()3. To draw, or cause to flow, by piercing.(Shak.)He has been tapping his liquors. (Addison.)4. (Mech.) To form an internal screw in (anything) by means of a tool called a tap; as, to tap a nut, a pipe, or tubing.()5. to connect a listening device to (a telephone or telegraph line) secretly, for the purpose of hearing private conversations; also, to obtain or record (information) by tapping; -- a technique used by law enforcement agencies investigating suspected criminals. In the United States it is illegal without a court order permitting it.()n. A kind of cloth prepared by the Polynesians from the inner bark of the paper mulberry; -- sometimes called also kapa.()n.[Sp. tapadera lid, cover.] One of the leather hoods which cover the stirrups of a Mexican saddle.()n. (Zol.) A Mexican spinous lizard (Phrynosoma orbiculare) having a head somewhat like that of a toad; -- called also horned toad.()