An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

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, → -metry.

Sebarsanji, from sebar, → trianle, + -sanji, → -metry.