D defs.my
Entry 1 sense Webster, 1913

Clepsydra

/klĕp'sĭdrə/ · Clep·sy·dra · IPA /ˈklɛpsɪdɹə/
01 n. A water clock; a contrivance for measuring time by the graduated flow of a liquid, as of water, through a small aperture. See Illust. in Ap…
  1. 1.
    A water clock; a contrivance for measuring time by the graduated flow of a liquid, as of water, through a small aperture. See Illust. in Appendix. See: Appendix