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

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 The Hong Kong hotel group is selling a duplex penthouse inside the Residences at the Mandarin Oriental, Honolulu. Demetrius Simms, Robb Report, 27 July 2022 Each penthouse will be a duplex unit with a private rooftop, where there will be a summer kitchen and pool. Tori Latham, Robb Report, 8 June 2022 Current projects include a duplex penthouse on Manhattan’s Fifth Avenue and a family apartment on Park Avenue. The Editors Of Elle Decor, ELLE Decor, 1 June 2022 Highlights for the new Norwegian Prima, the first in a new class of ships for the line, will include a duplex theater with seats that fold down to create space for a massive nightclub and several new dining concepts with rotating menus. Ramsey Qubein, Forbes, 20 Mar. 2022 The project on 22 acres at FM 306 and Common Street will include 126 duplex-style homes with 252 units. Madison Iszler, San Antonio Express-News, 8 Mar. 2022 Authorities determined that the fire started after an electric space heater sparked in a duplex unit. Chelsey Sanchez, Harper's BAZAAR, 19 Jan. 2022 Once combined, the duplex penthouse will comprise about 6,100 interior square feet. Helena Madden, Robb Report, 24 Jan. 2022 Meanwhile, the owners of the top two floors in the Palmolive have had that duplex penthouse on the market since last year for $11.9 million. Bob Goldsborough, chicagotribune.com, 7 Jan. 2022 Recent Examples on the Web: Noun The dinners will each be hosted by a Harlan expert and cooked by a Wynn executive chef in settings few guests get to see, like a palatial two-story Encore duplex suite. Andrea Bennett, Robb Report, 5 Aug. 2022 Some California cities aim to blunt the new duplex law With California on the verge of allowing multi-unit housing in neighborhoods previously reserved for single-family homes, some cities are rushing to pass restrictions on the new developments. Laura Blasey, Los Angeles Times, 30 Nov. 2021 In addition to the new duplex housing Mexico and Panama, the village is adding buildings to showcase the Philippines, Peru, India, Palestine, Turkey, Korea, and Chamorros. John Wilkens, San Diego Union-Tribune, 9 Oct. 2021 One of the bills, SB9, will allow lot-splitting and duplex-building across most lots zoned for single-family use. Susie Neilson, San Francisco Chronicle, 22 Sep. 2021 The duplex residence can be customized to have just two or up to four bedrooms, which can be decided upon purchase to meet the buyer’s specific needs. Emma Reynolds, Robb Report, 19 July 2022 But generating the most concern is a duplex that dominates the corner with one front door at 820 Fort Stockton Drive and its other entrance around the corner at 4053 Goldfinch St. Diane Bellcolumnist, San Diego Union-Tribune, 9 July 2022 As such, the residents of a neighboring duplex, for instance, may end up touching or consuming the chemicals without their knowledge. Doug Johnson, Ars Technica, 7 July 2022 Ann, in her late thirties lives in a western suburb, in a modest duplex house, comfortably furnished. Judy Sammon, cleveland, 17 May 2022 See More

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.

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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Dictionary Entries Near duplex



duplex apartment

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Last Updated

8 Aug 2022

Cite this Entry

“Duplex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/duplex. Accessed 11 Aug. 2022.

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More Definitions for duplex


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

Nglish: Translation of duplex for Spanish Speakers


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