D defs.my
Entry 1 sense Webster, 1913

Water clock

/wôt'-ẽr kläk/ · Wa·ter clock · IPA
01 An instrument or machine serving to measure time by the fall, or flow, of a certain quantity of water; a clepsydra.
  1. 1.
    An instrument or machine serving to measure time by the fall, or flow, of a certain quantity of water; a clepsydra.