/ Dictionary / Index S Severinus: Meaning and Definition of Find definitions for: Sev•er•i•nus Pronunciation: (sev"u-rī'nus), [key] — n. dieda.d.640, pope 640. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. severe combined immune deficiency severity Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language