complex

noun
com·​plex | \ ˈkäm-ˌpleks How to pronounce complex (audio) \

Definition of complex

 (Entry 1 of 3)

1 : a whole made up of complicated or interrelated parts a complex of welfare programs the military-industrial complex
2a : a group of culture traits relating to a single activity (such as hunting), process (such as use of flint), or culture unit
b(1) : a group of repressed desires and memories that exerts a dominating influence upon the personality a guilt complex
(2) : an exaggerated reaction to or preoccupation with a subject or situation He has always had a complex about spiders. She has a weight complex. Not being able to find a job was giving me a complex.
c : a group of obviously related units of which the degree and nature of the relationship is imperfectly known
d : the sum of factors (such as symptoms) characterizing a disease or condition primary tuberculous complex
3 : a chemical association of two or more species (such as ions or molecules) joined usually by weak electrostatic bonds rather than covalent bonds
4 : a building or group of buildings housing related units an apartment complex a sports complex

complex

adjective
com·​plex | \ käm-ˈpleks How to pronounce complex (audio) , kəm-ˈpleks, ˈkäm-ˌpleks\

Definition of complex (Entry 2 of 3)

1a : composed of two or more parts : composite a complex mixture of chemicals
b(1) of a word : having a bound form as one or more of its immediate constituents Unmanly is a complex word.
(2) of a sentence : consisting of a main clause and one or more subordinate clauses
2 : hard to separate, analyze, or solve a complex problem
3 : of, concerned with, being, or containing complex numbers a complex root complex analysis

complex

verb
com·​plex | \ käm-ˈpleks How to pronounce complex (audio) , kəm-ˈpleks, ˈkäm-ˌpleks\
complexed; complexing; complexes

Definition of complex (Entry 3 of 3)

transitive verb

1 : to make complex or into a complex
2 : chelate

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Other Words from complex

Adjective

complexly adverb
complexness noun

Verb

complexation \ ˌkäm-​ˌplek-​ˈsā-​shən How to pronounce complexation (audio) , kəm-​ \ noun

Choose the Right Synonym for complex

Adjective

complex, complicated, intricate, involved, knotty mean having confusingly interrelated parts. complex suggests the unavoidable result of a necessary combining and does not imply a fault or failure. a complex recipe complicated applies to what offers great difficulty in understanding, solving, or explaining. complicated legal procedures intricate suggests such interlacing of parts as to make it nearly impossible to follow or grasp them separately. an intricate web of deceit involved implies extreme complication and often disorder. a rambling, involved explanation knotty suggests complication and entanglement that make solution or understanding improbable. knotty ethical questions

The Complex Origins of Complex

The word complex lives up to its name, as it contains multiple parts of speech and senses. It serves as an adjective, a noun, and, less commonly, as a verb. The verb use is the oldest of the three, with an original meaning of “to join or unite.” Complex comes from the Latin complecti, which means “to entwine around, to embrace,” a word that is based in part on plectere (“to braid”). English has a number of other words that can be traced to plectere, including perplex, plexus (“an intricately interwoven combination of elements or parts in a cohering structure”), and amplexus (“the mating embrace of some amphibians, such as frogs and toads”).

Examples of complex in a Sentence

Noun

She has a complex about her appearance. a complex of protein molecules

Adjective

The house's wiring is complex. The situation is more complex than you realize.

Verb

there's no need to complex what should be a simple process for obtaining a building permit
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Recent Examples on the Web: Noun

The Nashville Yards complex is right off the interstate downtown, but that section of I-40 bottlenecks with every wreck, which occurs daily. Cari Wade Gervin, Curbed, "Will Amazon be good for Nashville?," 21 Nov. 2018 Today, the riverside complex is a hotbed for Brooklyn businesses, startups, and studios, from Catbird, to Mast Brothers, to photographer Sebastian Kim. Elise Taylor, Vogue, "How an Industrial Space in Brooklyn Was Transformed for the CFDA/Vogue Fashion Fund Awards Dinner," 6 Nov. 2018 The chic Loyly complex is typical of the new trend, with its saunas finely crafted from warm woods, a restaurant serving fashionable Nordic cuisine, and a seaside terrace for lounging. Rick Steves' Europe, The Seattle Times, "Helsinki holds its own among Nordic capitals," 18 Sep. 2018 The apartment complex is just a few blocks from Dallas' police headquarters. Ryan Tarinelli, Fox News, "Police: Dallas officer mistakes apartment for own, kills man," 7 Sep. 2018 The addition flows with the same brick and cream exterior color scheme as the original historic home, and the entire complex is a nonprofit run by the county’s leisure services department, which offers free admission to guests. Jennifer Bradley Franklin, Condé Nast Traveler, "3 Best Day Trips from Atlanta," 23 Aug. 2018 The 5,000-square-foot complex in the West Wing is where key national security discussions are held and decisions are made. Emily Stewart, Vox, "Omarosa recorded John Kelly in the situation room — and she’s got the tapes to prove it," 12 Aug. 2018 The Pearland Area Dad’s Club complex will be hosting the four-day tournament and maybe a five-day event should an IF contest be needed. Robert Avery, Houston Chronicle, "District champion Pearland West 11s riding wave of momentum for sectionals," 8 July 2018 The complex is a 15,000-square-foot food hall maze of bars, dining areas, markets and distillery operations at 351 Monon Trail, a block south of Main Street in Carmel. Liz Biro, Indianapolis Star, "Sun King Distillery in Carmel: What to know before you go," 3 July 2018

Recent Examples on the Web: Adjective

There are a lot of complex questions without a lot of easy answers. Rachel Epstein, Marie Claire, "Anissa Gray's 'The Care and Feeding of Ravenously Hungry Girls' Is #ReadWithMC's March Pick," 25 Feb. 2019 And even though most of us might not create the gorgeous and complex pysanky designs, many people dye at least a dozen or two for Easter (there are 230 million dozen eggs sold during the Easter season!). Arricca Elin Sansone, Country Living, "The History of Easter Eggs and Why They're Decorated," 25 Feb. 2019 Teachers unions oppose complex legislation under consideration that, among other things, would create the state's first charter schools and allow education savings accounts for parents to pay for private school. John Raby, The Seattle Times, "Despite bill’s demise, W.Va. teachers to strike for 2nd day," 20 Feb. 2019 Lagorio-Chafkin readily acknowledges that Reddit still has an uphill battle in terms of navigating this complex terrain. Jennifer Ouellette, Ars Technica, "Book tells the inside story of how Reddit came to be the Internet’s “id”," 30 Dec. 2018 The central banker said in response to an audience question about why wage gains haven’t been better in a strong job market that there are lot of complex factors at play. Michael S. Derby, WSJ, "San Francisco Fed Chief Supports Gradual Rate Rises," 12 Nov. 2018 Beneath these more obvious contradictions, there were many more complex factors. Julia Azari, Vox, "Narratives are simple. Elections are complicated.," 8 Nov. 2018 Oh, and the entire process takes six or seven years because of the complex trajectory a spaceship would need to follow in order to reach the tiny, innermost planet. Meghan Bartels, Space.com, "What Would It Take to Land on Mercury? It's Time to Find Out, Scientists Say," 30 Aug. 2018 The Wild Boars transfixed people in Thailand and elsewhere after a group of team members, ages 11 to 16, went exploring in the Tham Luang Nang Non cave complex with Ekapol, 25, after soccer practice June 23. Matt Blomberg, latimes.com, "There's a reason that the soccer team rescued from a cave in Thailand was so tough and resilient," 11 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'complex.' 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 complex

Noun

1643, in the meaning defined at sense 1

Adjective

1645, in the meaning defined at sense 1a

Verb

1658, in the meaning defined at sense 1

History and Etymology for complex

Noun

Late Latin complexus totality, from Latin, embrace, from complecti — see complex entry 2

Adjective

Latin complexus, past participle of complecti to embrace, comprise (a multitude of objects), from com- + plectere to braid — more at ply

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Statistics for complex

Last Updated

9 Mar 2019

Look-up Popularity

Time Traveler for complex

The first known use of complex was in 1643

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More Definitions for complex

complex

noun

English Language Learners Definition of complex

 (Entry 1 of 2)

: a group of buildings, apartments, etc., that are located near each other and used for a particular purpose
: an emotional problem that causes someone to think or worry too much about something
: a group of things that are connected in complicated ways

complex

adjective

English Language Learners Definition of complex (Entry 2 of 2)

: having parts that connect or go together in complicated ways
: not easy to understand or explain : not simple
grammar : consisting of a main clause and one or more additional clauses

complex

adjective
com·​plex | \ käm-ˈpleks How to pronounce complex (audio) , kəm-ˈpleks, ˈkäm-ˌpleks\

Kids Definition of complex

1 : not easy to understand or explain : not simple complex instructions
2 : having parts that go together in complicated ways a complex invention

complex

adjective
com·​plex | \ käm-ˈpleks How to pronounce complex (audio) , kəm-ˈ How to pronounce complex (audio) , ˈkäm-ˌ\

Medical Definition of complex

 (Entry 1 of 3)

1 : having many varied interrelated parts, patterns, or elements and consequently hard to understand complex behavior a complex personality complex plants and animals
2 : formed by the union of simpler chemical substances complex proteins

complex

noun
com·​plex | \ ˈkäm-ˌpleks How to pronounce complex (audio) \

Medical Definition of complex (Entry 2 of 3)

1 : a group of repressed memories, desires, and ideas that exert a dominant influence on the personality and behavior a guilt complex — see castration complex, electra complex, inferiority complex, oedipus complex, persecution complex, superiority complex
2 : a group of chromosomes arranged or behaving in a particular way — see gene complex
3 : a chemical association of two or more species (as ions or molecules) joined usually by weak electrostatic bonds rather than by covalent bonds
4 : the sum of the factors (as symptoms and lesions) characterizing a disease primary tuberculous complex

complex

transitive verb
com·​plex | \ käm-ˈpleks How to pronounce complex (audio) , kəm-ˈ How to pronounce complex (audio) , ˈkäm-ˌ\

Medical Definition of complex (Entry 3 of 3)

1 : to form into a complex RNA complexed with protein
2 : chelate

intransitive verb

: to form a complex hormones which must complex with specific receptors

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Comments on complex

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