Source : Webster's Revised Unabridged Dictionary (1913)

Hydrant \Hy"drant\, n. [Gr. ? to irrigate, fr. "y`dwr water. See
   {Hydra}.]
   A discharge pipe with a valve and spout at which water may be
   drawn from the mains of waterworks; a water plug.

Source : WordNet®

hydrant
     n 1: a faucet for drawing water from a pipe or cask [syn: {water
          faucet}, {water tap}, {tap}, {spigot}]
     2: a discharge pipe with a valve and spout at which water may
        be drawn from the mains of waterworks