Etymology 1

Noun

1. A tapering cylindrical pin or peg used to stop the vent in a cask; a spigot.
2. A device used to dispense liquids.

   We don't have bottled water, you'll have to get it from the tap.

3. A device used to cut an internal screw thread. (External screw threads are cut with a die.)

   We drilled a hole and then cut the threads with the proper tap to match the valve's thread.

4. A connection made to an electrical or fluid conductor without breaking it.

   The system was barely keeping pressure due to all of the ill advised taps along its length.

Verb

1. To furnish with taps.
2. To draw off liquid from a vessel

   He tapped a new barrel of beer.

3. To place a listening or recording device on a telephone or wired connection.

   They can't tap the phone without a warrant.

4. To intercept a communication without authority.

   He was known to tap Cable TV and satellite dishes.

5. To cut an internal screw thread.

   Tap an M3 thread all the way through the hole.

6. To have sexual intercourse with.

   I would tap that hot girl over there. or, more informally, I'd tap that

Noun

1. Device used to listen in secretly on telephone calls.

Etymology 3

Verb

1. To strike lightly.
2. To touch one's finger, foot, or other body parts on a surface (usually) repeatedly.

   He was so nervous he began to tap his fingers on the table.

   She tapped her companion on the back to indicate that she was ready to go.

3. To make a sharp noise.

   The tree, swaying in the breeze, began to tap on the window pane.

4. To designate for some duty or for membership, as in 'a tap on the shoulder'.

Noun

1. A repeated touching of one's hands, foot or other body part.

   When Steve felt a tap on his shoulder, he turned around.