n A measure; a standard of measure; an instrument to determine dimensions, distance, or capacity; a standard
n Any instrument for ascertaining or regulating the level, state, dimensions or forms of things; as, a rain gauge; a steam gauge.
n (context|mathematics|analysis) A semi-norm; a function that assigns a non-negative size to all vectors in a vector space.
v (transitive) To measure or determine usually with a gauge; to measure the capacity, character, or ability of; to estimate; to judge of.