Pl. -as, and -æ. [Lat., a. Gr. κλεψύδρα, f. Gr. κλεψ- combining form from κλέπτ-ειν to steal + ὔδωρ water. The name was also applied to intermittent fountains or ‘ebbing wells.’ Blount has the Fr. form clepsydre.] An instrument used by the ancients to measure time by the discharge of water; a water-clock.
1646. Sir T. Browne, Pseud. Ep., V. xviii. 259. They measured the hours not only by … water in glasses called Clepsydræ, but also by sand in glasses called Clepsammia.
1656. Blount, Glossogr., Clepsydre (clepsydra), a water-Dyal.
1741–70. Eliz. Carter, Lett. (1808), 43. You are not one of those orators whom I could wish confined to a Clepsydra.
1837. Whewell, Hist. Induct. Sc. (1857), I. 149. Clepsydras … were used by astronomers.
1878. Lockyer, Stargazing, 36.
