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 complex (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 Austin police say active attack/shooter scene just down the road - likely an apartment complex - from Arboretum area in Austin. NBC News, "3 dead in 'domestic' shooting in Austin, Texas; officials say scene remains active," 18 Apr. 2021 The Scarborough site housed a complex of buildings, including one with a circular central room and several rooms leading off of it, as well as a bathhouse. Livia Gershon, Smithsonian Magazine, "Archaeologists Unearth Sprawling Roman Ruins Unlike Any Found in the U.K.," 16 Apr. 2021 Land to the east and west of the site is vacant, but there is an apartment building, the 644-unit Greenfield Village complex, across the street on Otay Mesa Road. Phillip Molnar, San Diego Union-Tribune, "San Diego gives initial thumbs up for more Otay Mesa housing," 15 Apr. 2021 In 2014, Malloy rejected a request from the federal government that would have used the underutilized, sprawling, 1,600-acre Southbury Training School complex to shelter as many as 2,000 migrant children from Central America. Christopher Keating, courant.com, "Connecticut Gov. Ned Lamont: Plans to bring migrant children from Texas border to former Middletown juvenile prison on hold for now," 15 Apr. 2021 The address corresponds with an apartment complex, where Google satellite images show residential units featuring balconies. Alex Mann, baltimoresun.com, "Gaithersburg police officers are reportedly shot at after parking complaint, authorities say," 14 Apr. 2021 One signature project in the 1980s was developing a large apartment complex and golf course in northwest suburban Lakemoor, the Lakemoor Country Club. Bob Goldsborough, chicagotribune.com, "Former Oakbrook Terrace developer Robert Krilich dies," 13 Apr. 2021 One of San Antonio’s top bar developers is teaming up with a noted fish and chips purveyor to launch a new pub and restaurant late this spring in the Inspire Downtown apartment complex, formerly The Vistana. Paul Stephen, San Antonio Express-News, "British pub and restaurant with fish and chips, The Dandy, to open in downtown San Antonio soon," 13 Apr. 2021 In this scenario, people form vessel-clogging antibodies to the complex of heparin and platelets (which help blood to clot when you get cut or injured), which start to aggregate into blood-flow-blocking clumps. Alice Park, Time, "FDA and CDC Recommend Pausing COVID-19 Vaccination With J&J-Janssen Shot While They Investigate Blood Clot Risks," 13 Apr. 2021 Recent Examples on the Web: Adjective Crews received the call just after 8:30 a.m. for a structure fire at the Summit Lake apartment complex on Millington Lane. Evan Frank, Milwaukee Journal Sentinel, "Want to help Hartland families displaced by a fire? A GoFundMe account has been set up," 6 Apr. 2021 Called Energía Sierra Juárez, the complex consists of 47 wind turbines with a capacity to generate 155 megawatts of electricity. Rob Nikolewski, San Diego Union-Tribune, "Sempra subsidiary buys wind farm in Baja for $80 million," 5 Apr. 2021 But we’ve been conditioned to believe such common sense may not be uttered, lest the media-Democrat complex portray us as the reincarnation of Jim Crow. Andrew C. Mccarthy, National Review, "Major League Baseball and the Voting-Rights Con," 3 Apr. 2021 Four people, including a child, were killed in a mass shooting at an office complex Wednesday, and a fifth person was transported to a local hospital in critical condition with a gunshot wound, Lt. Jennifer Amat said. Madeline Holcombe, CNN, "At least 20 mass shootings have taken place in the two weeks since the metro Atlanta spa attacks left 8 dead," 1 Apr. 2021 On March 23, a Royalton Road resident called police after making a surprising discovery in their apartment complex parking lot. John Benson, cleveland, "Aggressive man with dog told not to return to Royalton Road business: Strongsville Police Blotter," 31 Mar. 2021 About 15 minutes later, police were called to an apartment complex 5 minutes away for a report of a fire and a person shot. Christine Condon, baltimoresun.com, "Police: 2 killed, 1 injured in shooting at Essex Royal Farms; another body found at nearby apartment complex," 28 Mar. 2021 More than two dozen cars in Wethersfield also were burglarized before dawn Thursday, and most of those thefts happened in apartment complex parking lots off the Berlin Turnpike, Lt. Donald Crabtree said. Christine Dempsey, courant.com, "Dozens of cars broken into in Newington and Wethersfield early Thursday," 25 Mar. 2021 Thursday’s ruling revives a lawsuit brought by a New Mexico woman who said she was wrongly shot when officers arrived at her apartment complex planning to arrest another person. David G. Savage, Los Angeles Times, "Supreme Court expands meaning of ‘seizure’ under 4th Amendment," 25 Mar. 2021

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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Time Traveler for complex

Time Traveler

The first known use of complex was in 1643

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Statistics for complex

Last Updated

22 Apr 2021

Cite this Entry

“Complex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/complex. Accessed 22 Apr. 2021.

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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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