Tap has several common meanings:

1. To strike or touch something lightly and quickly. You might tap someone on the shoulder to get their attention, or tap your pencil on your desk while thinking. A woodpecker taps its beak against a tree trunk. The key is that it's gentle and brief, not a heavy hit or push.
2. A device that controls the flow of water or other liquids, also called a faucet. You turn the tap on to wash your hands and turn it off when you're done. In England and other countries, people say “tap” more often than Americans, who usually say “faucet.”
3. To make use of a resource or ability. A basketball coach might tap into a player's natural speed by designing plays that showcase it. If you're struggling with a science project, you might tap your older sister's knowledge by asking for her help. It means accessing something that's already there but not yet being used.

The word can also refer to a type of dance in which dancers wear special shoes with metal plates that make rhythmic clicking sounds, called tap dancing. Performers like Savion Glover have elevated tap dancing into a spectacular art form.