1. (noun)soluble glass, water glass, sodium silicate a viscous glass consisting of sodium silicate in solution; used as a cement or as a protective coating and to preserve eggs
2. (noun)water glass a glass for drinking water
3. (noun)water gauge, water gage, water glass gauge for indicating the level of water in e.g. a tank or boiler or reservoir
4. (noun)water clock, clepsydra, water glass clock that measures time by the escape of water