/ Dictionary / Index P prime rate: Meaning and Definition of Find definitions for: prime' rate' Pronunciation: [key] — Banking. Banking. the minimum interest rate charged by a commercial bank on short-term business loans to large, best-rated customers or corporations. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. primer prime ribs Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language