Definition
A hand tool consisting of a removable cylindrical socket that fits onto a separate handle or driver. The socket slips over the head of a bolt or nut and turns it when the handle is rotated. Sockets come in different sizes and drive shapes (commonly 1/4, 3/8, and 1/2-inch square drives) and can be swapped on the same handle to fit different fasteners.
Plain English
A wrench made in two parts: a small metal cup that fits over a bolt head, and a separate handle that turns it. You change the cup to match the size of the bolt.
Context Anchor
Seen during aircraft maintenance, inspection work, and small hardware removal or installation around the aircraft.
Derivation
Socket comes from Old French soquete, meaning a small ploughshare or hollow piece. The name describes the shape of the tool: a hollow cylinder that receives the bolt head, much like a socket receives a plug.
Why Pilots Care
Pilots performing preventive maintenance authorized under FAR Part 43 will use socket wrenches for tasks such as changing tires, servicing wheel bearings, or removing inspection panels. Using the correct socket size prevents rounding off the bolt head, which can turn a simple job into a major repair.
Intuition Check
Do not confuse socket here with an electrical outlet. In this term, the socket is the hollow metal piece that fits over the nut or bolt head.
Example Sentence 1
The mechanic selected a 1/2-inch socket wrench to remove the wheel nuts during the tire change.
Example Sentence 2
During preflight preparation, a socket wrench was used to secure the battery terminals in the compartment.