Definitions of tap:

• noun:   a light touch or stroke
• noun:   a plug for a bunghole in a cask
• noun:   a tool for cutting female (internal) screw threads
• noun:   a small metal plate that attaches to the toe or heel of a shoe (as in tap dancing)
• noun:   the act of tapping a telephone or telegraph line to get information
• noun:   a faucet for drawing water from a pipe or cask
• noun:   the sound made by a gentle blow
• noun:   a gentle blow
• verb:   make light, repeated taps on a surface

  Example: "He was tapping his fingers on the table impatiently"

• verb:   draw from or dip into to get something

  Example: "Tap one's memory"

• verb:   furnish with a tap or spout, so as to be able to draw liquid from it

  Example: "Tap a cask of wine"

• verb:   strike lightly

  Example: "He tapped me on the shoulder"

• verb:   cut a female screw thread with a tap
• verb:   pierce in order to draw a liquid from

  Example: "Tap a maple tree for its syrup"

• verb:   draw (liquor) from a tap

  Example: "Tap beer in a bar"

• verb:   walk with a tapping sound
• verb:   tap a telephone or telegraph wire to get information

  Example: "The FBI was tapping the phone line of the suspected spy"

• verb:   draw from; make good use of
• verb:   dance and make rhythmic clicking sounds by means of metal plates nailed to the sole of the dance shoes

  Example: "Glover tapdances better than anybody"

• verb:   make a solicitation or entreaty for something; request urgently or persistently