/ Dictionary / Index I installment plan: Meaning and Definition of Find definitions for: install'ment plan" Pronunciation: [key] a system for paying for an item in fixed amounts at specified intervals. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. installment Instamatic Related Content Daily Word Quiz: philanthropy Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language