Definition
A socket wrench fitting whose internal opening has twelve evenly spaced points (or 'flutes') around its circumference, allowing it to engage a six-sided (hex) bolt head or nut at any of twelve positions — every 30 degrees of rotation.
Plain English
A socket with twelve notches inside instead of six. It still fits a regular six-sided bolt, but you can slip it on at twice as many angles, which makes it much easier to use in tight spaces where you can only swing the wrench a little bit at a time.
Context Anchor
Seen in aircraft maintenance and tool-selection discussions, especially when working around engine compartments, panels, brackets, or other cramped areas.
Derivation
Named for the twelve points (corners) inside the socket opening. The twelve-point design is sometimes called 'double hex' because it is effectively two hexagons overlaid at a 30-degree offset.
Why Pilots Care
Allows mechanics to work more efficiently on engines and airframe components without repositioning the wrench as frequently.
Analogy
Think of a clock face. A six-point socket only fits at the 12, 2, 4, 6, 8, and 10 positions. A twelve-point socket also fits at the 1, 3, 5, 7, 9, and 11 positions — twice as many ways to slip it on.
Intuition Check
A twelve-point socket is not mainly for twelve-sided aircraft hardware. In most use, it is a socket that can fit ordinary six-sided nuts and bolt heads from more angles.
Example Sentence 1
The mechanic reached for a twelve-point socket because the engine mount bolt was tucked behind a bracket that only allowed a short swing of the ratchet.
Example Sentence 2
Twelve-point sockets are preferred over six-point sockets when working around obstacles on the aircraft.