1911 Encyclopædia Britannica/Brachistochrone

BRACHISTOCHRONE (from the Gr. βράχιστος, shortest, and χρόνος, time), a term invented by John Bernoulli in 1694 to denote the curve along which a body passes from one fixed point to another in the shortest time. When the directive force is constant, the curve is a cycloid (q.v.); under other conditions, spirals and other curves are described (see Mechanics).