a screw (often without a head) that fits into the boss or hub of a wheel or cam etc. and prevents motion of the part relative to the shaft on which it is mounted | slang for sexual intercourse |
a screw that is used to adjust the tension on a spring | a fastener with a tapered threaded shank and a slotted head |
| a propeller with several angled blades that rotates to push against water or air |
| a simple machine of the inclined-plane type consisting of a spirally threaded cylindrical rod that engages with a similarly threaded hole |
| someone who guards prisoners |