Noun
Any wheel worked by hand; esp., one the rim of which serves as the handle by which a valve, car brake, or other part is adjusted.
Source: Webster's dictionaryBench micrometers of the "super-mic" class entirely obviate this interuser variation by having the user dial the handwheel until a needle reads zero on a gauge, producing the same pressure on every reading. Source: Internet
This cylinder is fitted with an overfill prevention device (OPD) valve, as evidenced by the trilobular handwheel. Source: Internet