rotameter

rotameter [roh-tam-i-ter, roh-tuh-mee-] Word Origin noun

1. an instrument for measuring the rate of flow of a liquid, consisting of a tapered vertical tube in which a small float is forced upward until its weight balances the fluid force.

Origin of rotameter partial translation of German Rotamesser (1911), equivalent to Rota(tion) rotation + Messer measurer, meter British Dictionary definitions for rotameter Rotameter noun

1. trademark a device used for measuring the flow of a fluid. It consists of a small float supported in a tapering glass by the flow of the fluid, the height of the float indicating the rate of flow