The Collaborative International Dictionary
Rhysimeter
Rhysimeter \Rhy*sim"e*ter\, n. [Gr. ??? flow + -meter.] An instrument, acting on the principle of Pitot's tube, for measuring the velocity of a fluid current, the speed of a ship, etc.
Wiktionary
rhysimeter
n. An instrument, acting on the principle of the pitot tube, for measure the velocity of a fluid current, the speed of a ship, etc.