**Bra*chys"to*chrone** (?), n. [Incorrect for *brachistochrone*, fr. Gr. shortest (superl. of 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*.

© Webster 1913.