[doo-pleks, dyoo-]
See more synonyms for duplex on Thesaurus.com
  1. duplex apartment.
  2. duplex house.
  3. paper or cardboard having different colors, finishes, or stocks on opposite sides.
  4. Printing.
    1. a method of reproducing an illustration using two halftone plates, one black and the other in a color.
    2. a printing press equipped to print both sides of a sheet in one pass.
  5. Genetics. a double-stranded region of DNA.
  1. having two parts; double; twofold.
  2. (of a machine) having two identical working units, operating together or independently, in a single framework or assembly.
  3. pertaining to or noting a telecommunications system, as most telephone systems, permitting the simultaneous transmission of two messages in opposite directions over one channel.
verb (used with object)
  1. to make duplex; make or change into a duplex: Many owners are duplexing their old houses for extra income.

Origin of duplex

1810–20; < Latin: twofold, double, equivalent to du(o) two + -plex -plex
Related formsdu·plex·i·ty, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for duplexity


  1. US and Canadian a duplex apartment or house
  2. a double-stranded region in a nucleic acid molecule
  1. having two parts
  2. machinery having pairs of components of independent but identical function
  3. permitting the transmission of simultaneous signals in both directions in a radio, telecommunications, or computer channel
Derived Formsduplexity, noun

Word Origin for duplex

C19: from Latin: twofold, from duo two + -plex -fold
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for duplexity



1817, "composed of two parts," from Latin duplex, from duo "two" (see two) + -plex, from Greek plax (genitive plakos) "flat surface." The noun sense of "house for two families; two-story apartment" is American English, 1922.

Online Etymology Dictionary, © 2010 Douglas Harper