/ Dictionary / Index S sero-: Meaning and Definition of Find definitions for: sero- Pronunciation: [key] a combining form representingin compound words: serology. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Sermon on the Mount serodiagnosis Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language