Definition
A hardened cutting tool used to cut internal threads inside a drilled hole, allowing a bolt or threaded fastener to screw into the material.
Plain English
A tool that cuts screw threads on the inside of a hole so a bolt can thread into it.
Context Anchor
Seen in aircraft maintenance when a mechanic is making or repairing a threaded hole for a screw or bolt.
Derivation
From Old English 'tæppa,' originally meaning a pin or peg used to plug a hole. The tool got the name because it works inside a hole, much like a peg fits into one.
Why Pilots Care
Threads cut by a tap must be the correct size and class for the fastener; an incorrect or damaged tapped hole can cause a fastener to strip, back out, or fail in service.
Intuition Check
Tap does not mean a light hit here, and it does not mean a faucet. In aircraft maintenance, a tap is a tool used to make or repair threads inside a hole.
Example Sentence 1
The technician used a tap to cut new threads in the engine case after the original threads were damaged.
Example Sentence 2
After drilling to the correct size, use a tap to cut threads that match the fastener.