/ Dictionary / Index S sinus node: Meaning and Definition of Find definitions for: si'nus node" Pronunciation: (sī'nus), [key] — Anat. Anat. See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sinus Meridianii Sinus of Valsalva Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language