A handheld instrument used for rapid calculations; have been replaced by pocket calculators; SYN. slipstick.
Mathematical instrument with pairs of logarithmic sliding scales, used for rapid calculations, including multiplication, division, and the extraction of square roots. It has been largely superseded by the electronic calculator.
It was invented 1622 by the English mathematician William Oughtred. A later version was devised by the French army officer Amédée Mannheim (1831–1906).