from
The Collaborative International Dictionary of English v.0.48
Brachystochrone \Bra*chys"to*chrone\, n. [Incorrect for
brachistochrone, fr. Gr. bra`chistos shortest (superl. of
brachy`s 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}.
[1913 Webster]