1. Consisting of three united; multiplied by three; threefold; as, a triple knot; a triple tie.
By thy triple shape as thou art seen. --Dryden.
2. Three times repeated; treble. See Treble.
3. One of three; third. [Obs.]
Triple crown, the crown, or tiara, of the pope. See Tiara, 2.
Triple-expansion steam engine, a compound steam engine in which the same steam performs work in three cylinders successively.
Triple measure Mus., a measure of tree beats of which first only is accented.
Triple ratio Math., a ratio which is equal to 3.
Triple salt Chem., a salt containing three distinct basic atoms as radicals; thus, microcosmic salt is a triple salt.
Triple star Astron., a system of three stars in close proximity.
Triple time Mus., that time in which each measure is divided into three equal parts.
Triple valve, in an automatic air brake for railroad cars, the valve under each car, by means of which the brake is controlled by a change of pressure in the air pipe leading from the locomotive.