/ Dictionary / Index D duplex pump: Meaning and Definition of Find definitions for: du'plex pump" Pronunciation: [key] a pair of direct-acting steam pumps so arranged that each pump begins its working stroke just as the other finishes its working stroke, so that the rate of flow of the fluid is nearly continuous. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. duplex process duplicable Related Content Daily Word Quiz: mamba Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language