/ Dictionary / Index D duplexer: Meaning and Definition of Find definitions for: du•plex•er Pronunciation: (d'plek-sur, dy'-), [key] — n. Electronics. an automatic electronic switching device that permits the use of the same antenna for transmitting and receiving. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: duplexer (Thesaurus) duplex apartment duplex house 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