/ Dictionary / Index S sine curve: Meaning and Definition of Find definitions for: sine' curve" Pronunciation: [key] — Math. Math. a curve described by the equation y = sin x, the ordinate being equal to the sine of the abscissa. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. sinecure sine die Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language