/ Dictionary / Index S sinal: Meaning and Definition of Find definitions for: si•nal Pronunciation: (sīn'l), [key] — adj. of, pertaining to, or involving a sinus. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sinai sinalbin Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language