Tri*an`gu*la"tion (?), n. [Cf. F. triangulation.] (Surv.) The series or
network of triangles into which the face of a country, or any portion
of it, is divided in a trigonometrical survey; the operation of
measuring the elements necessary to determine the triangles into which
the country to be surveyed is supposed to be divided, and thus to fix
the positions and distances of the several points connected by them.
Tri"ar*chy (?), n.; pl. Triarchies (#). [Gr. &?;; &?; (see Tri-) + &?;
to rule.] Government by three persons; a triumvirate; also, a country
under three rulers. Holland.
Tri*a"ri*an (?), a. [L. triarii, pl., a class of Roman soldiers who
formed the third rank from the front, fr. tres, tria, three.] Occupying
the third post or rank. [Obs.] Cowley.
Tri`ar*tic"u*late (?), a. [Pref. tri- + articulate.] (Zoöl.) Having
three joints.
Tri"as (?), n. [L., triad. See Triad.] (Geol.) The formation situated
between the Permian and Lias, and so named by the Germans, because
consisting of three series of strata, which are called in German the
Bunter sandstein, Muschelkalk, and Keuper.
Tri*as"sic (?), a. (Geol.) Of the age of, or pertaining to, the Trias.
— n. The Triassic formation.
Tri*at"ic (?), a. (Naut.) A term used in the phrase triatic stay. See
under Stay.
Tri`a*tom"ic (?), a. [Pref. tri- + atomic.] (Chem.) (a) Having three
atoms; — said of certain elements or radicals. (b) Having a valence of
three; trivalent; sometimes, in a specific sense, having three hydroxyl
groups, whether acid or basic; thus, glycerin, glyceric acid, and
tartronic acid are each triatomic.
Trib"al (?), a. Of or pertaining to a tribe or tribes; as, a tribal
scepter. Bp. Warburton.
Trib"al*ism (?), n. The state of existing in tribes; also, tribal
feeling; tribal prejudice or exclusiveness; tribal peculiarities or
characteristics.
Tri*ba"sic (?), a. [Pref. tri- + basic.] (Chem.) Capable of
neutralizing three molecules of a monacid base, or their equivalent;
having three hydrogen atoms capable of replacement by basic elements on
radicals; — said of certain acids; thus, citric acid is a tribasic
acid.
Trib"ble (?), n. (Paper Manuf.) A frame on which paper is dried.
Knight.
Tribe (?), n. [L. tribus, originally, a third part of the Roman people,
afterwards, a division of the people, a tribe; of uncertain origin: cf.
F. tribu.]
1. A family, race, or series of generations, descending from the same
progenitor, and kept distinct, as in the case of the twelve tribes of
Israel, descended from the twelve sons of Jacob. "The Lion of the tribe
of Juda." Rev. v. 5.
A wealthy Hebrew of my tribe.
Shak.
2. (Bot.) A number of species or genera having certain structural
characteristics in common; as, a tribe of plants; a tribe of animals.
By many recent naturalists, tribe has been used for a group of animals
or plants intermediate between order and genus.
3. A nation of savages or uncivilized people; a body of rude people
united under one leader or government; as, the tribes of the Six
Nations; the Seneca tribe.
4. A division, class, or distinct portion of a people, from whatever
cause that distinction may have originated; as, the city of Athens was
divided into ten tribes.
5. (Stock Breeding) A family of animals descended from some particular
female progenitor, through the female line; as, the Duchess tribe of
shorthorns.