What is "water gage"

Water gauge \Wa"ter gauge`\ [Written also water gage.]

1. A wall or bank to hold water back.
   --Craig.

2. An instrument for measuring or ascertaining the depth or quantity of water, or for indicating the height of its surface, as in the boiler of a steam engine. See Gauge.

n. gauge for indicating the level of water in e.g. a tank or boiler or reservoir [syn: water gauge, water glass]