/ Dictionary / Index T trigonometry: Meaning and Definition of Find definitions for: trig•o•nom•e•try Pronunciation: (trig"u-nom'i-trē), [key] — n. the branch of mathematics that deals with the relations between the sides and angles of plane or spherical triangles, and the calculations based on them. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: trigonometry (Thesaurus) trigonometric series trigonous Related Content Daily Word Quiz: gregarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language