/ Thesaurus / P Synonyms of prime interest rate Find synonyms for: Noun1. prime interest rate, interest rate, rate of interestusage: the interest rate on short-term loans that banks charge their commercial customers with high credit ratingsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: winsome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language