[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

Related Words for duplex

double, twin

Examples from the Web for duplex

Contemporary Examples of duplex

Historical Examples of duplex

British Dictionary definitions for duplex


  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 duplex

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