(tap) noun
1. An arrangement for drawing out liquid, as beer from a cask.
2. A faucet or cock; spigot; also, a plug or stopper to close an opening in a cask or other vessel.
3. Liquor drawn from a tap; also, a particular liquor or quality of liquor contained in casks.
4. Brit. A place where liquor is served; a bar; taproom.
5. A tool for cutting internal screw threads.
6. A point of connection for an electrical circuit.
7. The act or an instance of wiretapping.
—on tap
1. Contained in a cask; ready for tapping: beer on tap.
2. Provided with a tap.
3. Available; ready.
—v.t. tapped, tap·ping
1. To provide with a tap or spigot.
2. To pierce or open so as to draw liquid from: to tap a sugar-maple tree.
3. To draw (liquid) from a container.
4. To make connection with: to tap a gas main.
5. To make connection with secretly: to tap a telephone wire.
6. To make an internal screw thread in with a tap: to tap a nut. [OE tœppa]

(tap) v. tapped, tap·ping v.t.
1. To touch or strike gently.
2. To make or produce by tapping.
3. To apply leather to (the sole or heel of a shoe) in repair.
—v.i.
4. To strike a light blow or blows, as with the finger tip.
—noun
1. A gentle or playful blow.
2. Leather, etc., affixed to a shoe sole or heel; also, a metal plate on the toe or heel of a tap-dancer's shoe.
3. plural A military signal by trumpet or beat of drum, sounded after tattoo, for the extinguishing of all lights in soldiers' quarters: often played after a military burial. [<OF taper]