Breadcrumb Home > Dictionary > Index S septi-: Meaning and Definition of Find definitions for: septi- Pronunciation: [key] a combining form meaning “seven,” used in the formation of compound words: septilateral. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. septet septic ✖ Related Content Daily Word Quiz: hortatory Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language