du·​plex | \ ˈdü-ˌpleks How to pronounce duplex (audio) also ˈdyü- \

Definition of duplex

 (Entry 1 of 3)

1a : having two principal elements or parts : double, twofold
b : having two complementary polynucleotide strands of DNA or of DNA and RNA
2 : allowing telecommunication in opposite directions simultaneously


duplexed; duplexing; duplexes

Definition of duplex (Entry 2 of 3)

transitive verb

: to make duplex



Definition of duplex (Entry 3 of 3)

: something duplex: such as
a : a 2-family house
c : a duplex molecule of DNA or of RNA and DNA

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Synonyms & Antonyms for duplex

Synonyms: Adjective

Antonyms: Adjective

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Duplex can describe a confusing variety of things, depending on the technical field. Most of us use it as a noun: a duplex can be either a two-family house or a two-story apartment. In computer science and telecommunications, duplex (or full-duplex) communication can go in both directions at once, while half-duplex communication can go only one way at a time. In other areas, just translate duplex as "double" and see if the sentence makes sense.

Examples of duplex in a Sentence

Adjective a duplex apartment with all of the bedrooms on the second floor Noun We live in the brick duplex.
Recent Examples on the Web: Adjective Installing theOUTlet is just as easy as installing any other duplex wall box. Maren Estrada, BGR, 17 June 2021 Full duplex printers can automatically print to both sides of a page. Dave Johnson, Forbes, 14 June 2021 The deal comes on the heels of another major transaction at 220 Central Park South last year, when another mystery buyer snapped up a duplex penthouse there for $100 million. Helena Madden, Robb Report, 8 June 2021 Opening for the summer season on July 1st, the hotel now houses 103 rooms and suites, which all come with private terraces, along with two signature suites and a duplex villa featuring private pool. Lauren Jade Hill, Forbes, 4 June 2021 Be prepared to get to really know your neighbors: Those who live in duplex homes report hearing significant noise from adjacent homes, though some residents, including Shana Boscak, have converted duplexes into single units. Christina Tkacik, baltimoresun.com, 3 June 2021 Installing theOUTlet is just as easy as installing any other duplex wall box. Maren Estrada, BGR, 17 May 2021 Installing theOUTlet is just as easy as installing any other duplex wall box. Maren Estrada, BGR, 17 May 2021 In recent years, the Jaurons have rented out the duplex town home at times, their listing agent, Lori Glattly of Berkshire Hathaway HomeServices Chicago, said. Bob Goldsborough, chicagotribune.com, 11 May 2021 Recent Examples on the Web: Noun Ramos, 29, has spent the last 10 years on 25th Avenue in a duplex owned by his family. Susie Neilson, San Francisco Chronicle, 6 May 2021 Cheryl lived by herself, in a duplex where two female friends lived next door. Lauren Clark, CBS News, 10 Apr. 2021 One of the competition’s prompts asked architects to submit a design for a standalone duplex on 2,500 square feet of space carved out of an existing single-family lot. Los Angeles Times, 17 May 2021 At 1,800 square feet, the unit is designed as a duplex—a rarity in its single-family neighborhood—and also features a pool and spacious yard. Noah Kirsch, Forbes, 26 Apr. 2021 The technology, based on Broadcom's full-duplex DOCSIS 4.0 computer chip, uses the same type of connections that are already installed in hundreds of millions of homes around the country, Comcast said. Chris Morris, Fortune, 22 Apr. 2021 Judging by the wisdom of the internet, where that house once stood is now a pretty duplex fronted by a thicket of semitropical plants. Los Angeles Times, 27 Apr. 2021 The sprawling penthouse is a duplex, with about 9,000 square feet of space on each level. Helena Madden, Robb Report, 19 Apr. 2021 Short-term vacation rentals, which have seen a rise in popularity in recent years, offer visitors a chance to stay in a home, duplex or other residential property for periods typically ranging from one night to a week or two. Barbara Henry, San Diego Union-Tribune, 20 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'duplex.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of duplex


1567, in the meaning defined at sense 1a


1833, in the meaning defined above


1922, in the meaning defined above

History and Etymology for duplex


Latin, from duo two + -plex -fold — more at two, -fold

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Last Updated

21 Jun 2021

Cite this Entry

“Duplex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/duplex. Accessed 23 Jun. 2021.

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More Definitions for duplex



English Language Learners Definition of duplex

: a building that is divided into two separate homes
: an apartment with two floors


du·​plex | \ ˈdü-ˌpleks How to pronounce duplex (audio) , ˈdyü- \

Kids Definition of duplex

: a house with two separate living spaces


du·​plex | \ ˈd(y)ü-ˌpleks How to pronounce duplex (audio) \

Medical Definition of duplex

: a molecule having two complementary polynucleotide strands of DNA or of DNA and RNA

Other Words from duplex

duplex adjective

More from Merriam-Webster on duplex

Thesaurus: All synonyms and antonyms for duplex

Nglish: Translation of duplex for Spanish Speakers


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