petcock

noun
pet·​cock | \ ˈpet-ˌkäk How to pronounce petcock (audio) \

Definition of petcock

: a small cock, faucet, or valve for releasing a gas (such as air) or draining

First Known Use of petcock

circa 1864, in the meaning defined above

History and Etymology for petcock

pet- (perhaps from petty) + cock

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