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.
Tri"ple, v. i. [imp. & p. p. Tripled (?); p. pr. & vb. n. Tripling
(?).] [Cf. F. tripler. See Triple, a.] To make threefold, or thrice as
much or as many; to treble; as, to triple the tax on coffee.
Tri"ple-crowned` (?), a. Having three crowns; wearing the triple crown,
as the pope.
Tri"ple-head`ed (?), a. Having three heads; three-headed; as, the
triple-headed dog Cerberus.
Trip"let (?), n. [From Triple.] 1. A collection or combination of three
of a kind; three united.