Brachystochrone

Bra‐chys″to‐chrone (�), n. [Incorrect for brachistochrone, fr. Gr. βράχιστοσ shortest (superl. of βραχύσ short) + � time: cf. F. brachistochrone.] (Math.) A curve, in which a body, starting from a given point, and descending solely by the force of gravity, will reach another given point in a shorter time than it could by any other path. This curve of quickest descent, as it is sometimes called, is, in a vacuum, the same as the cycloid.