(1) A device for indicating the magnitude or position of a thing in specific units, when such magnitude or position undergoes change, for example: The elevation of a water surface, the velocity of flowing water, the pressure of water, the amount or intensity of precipitation, the depth of snowfall, etc. (2) The act or operation of registering or measuring the magnitude or position of a thing when these characteristics are undergoing change. (3) The operation, including both field and office work, of measuring the discharge of a stream of water in a waterway.
A gage is a standard measurement of the thickness of metal sheets or wire (and bearing a relation to the weight of the metal). Also a term for the distance measured between rSailroad rails; (standard is 4 ft. 8½ in.).