noun
1. : water clock , clepsydra
2. : a glass vessel for holding water: as
a. : a drinking glass : tumbler
b. : a container for growing a flowering bulb (as a hyacinth) in water
c. archaic : a finger bowl of glass
3. : an instrument consisting of an open box or tube with a glass bottom used for examining objects in or under the water (as upon the sea bottom in shallow places)
4.
a. : a water-soluble substance consisting of sodium silicate Na 2 O. x SiO 2 of varying composition that is found in commerce as a glassy mass, a stony powder, or a viscous syrupy liquid dissolved in water that is used chiefly as a cement and adhesive, as a builder for soaps and synthetic detergents, as a protective coating and fireproofing agent in papermaking and in the textile industry, in making artificial stone, and in preserving eggs — called also soluble glass
b. : a similar substance consisting of potassium silicate — called also potash water glass
5. : water gage 1