The branch of mathematics dealing with the relations of the sides and angles of triangles; also
the various algebraic functions of these relations.
From N.L. trigonometria, from Gk. trigonon "triangle"
(from tri-, → three, + gonia "angle,"
cognate with Pers. zânu "knee") + metron,
Sebarsanji, from sebar, → trianle, +
-sanji, → -metry.