D defs.my
Entry 1 sense Webster, 1913

petcock

/(pĕt"kŏk`)/ · pet·cock · IPA /ˈpɛtkɒk/
01 n. A small cock or faucet or valve for letting out air or releasing compression, or for draining a vessel.
  1. 1.
    A small cock or faucet or valve for letting out air or releasing compression, or for draining a vessel.