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

Because those complexes account for several hundred units, the real number of buildings is somewhere below 2,000. James Briggs, Indianapolis Star, "11 times Mayor Joe Hogsett said misleading things about his blighted housing fix," 11 June 2019 Steep terrain, high altitude, snow and the remote location made the rescue effort complex. Kieran Nicholson, The Denver Post, "Climber rescued by Blackhawk helicopter after falling 200 feet down snowy Boulder County mountain," 11 June 2019 The complex would have included a high-tech, gameified driving range as well as a 578-spot parking deck paid for by the New Orleans Exhibition Hall Authority. Jennifer Larino, nola.com, "Market Street power plant has sat vacant for decades. Now there’s a renewed push to develop it.," 11 June 2019 This massive outdoor water complex has a giant splash pad with multiple whimsical shooting water features and an Olympic-sized pool with diving boards and a fantastic twisty blue slide, plus a smaller sized pool for tubing and kick-boarding. Jessica Yadegaran, The Mercury News, "7 sensational Bay Area pools to escape the heat," 10 June 2019 For example, independent living complexes may have individual locks on residents' units _ although nurses or other staff may have keys for emergencies. Charles Scudder, chicagotribune.com, "Six security tips to follow before you move your loved one into a senior-living community," 9 June 2019 The Jackson administration began a search this week for a consultant to help plan for the complex and will accept proposals from candidates until July 8. Robert Higgs, cleveland.com, "Cleveland strategy for curbing illegal dirt bike riders involves series of summer events, developing professional-grade track," 5 June 2019 Tens of thousands of visitors returned once more to the annual Frieze New York art fair on Randall’s Island last weekend, where a sprawling white tent complex pops up like a mirage. Kyle Chayka, WSJ, "At Art Fairs, the Chairs Are Just as Considered as the Art," 7 May 2019 Its physical substrate, the thalamo-cortical complex that provides consciousness with its highly elaborate content, begins to be in place between the 24th and 28th week of gestation. Jennifer Wright, Harper's BAZAAR, "Why the Abortion Movie Unplanned Is Factually Incorrect," 16 Apr. 2019

Recent Examples on the Web: Adjective

The wrenching details of her last days have shined a light on Israel’s complex and stringent system for issuing Gaza exit permits. Isabel Debre, BostonGlobe.com, "Sick Gaza child caught in Israeli permit system dies alone," 12 June 2019 The 2014-2016 West African Ebola epidemic started in Guinea and was the largest and most complex outbreak since the virus was first discovered in 1976, according to the World Health Organization. NBC News, "What is Ebola? What to know about symptoms, vaccine, outbreaks," 12 June 2019 The biggest and most complex cases are where physicians can earn CME credits. Edward Baig, USA TODAY, "Your doctor may be playing medical video games at work. That could be good for your health," 12 June 2019 Their relationship was always very complex and complicated. Ashley Boucher, PEOPLE.com, "Selena Gomez Deletes the Last Photo of Justin Bieber, a Birthday Shoutout, from Her Instagram," 10 June 2019 The requirements of Section 120 were complex and daunting. Sallie Tisdale, Harper's magazine, "Catechism of the Waters," 10 June 2019 Crises are complex and multifaceted and strike in wealthier countries, too. Moisés Naím, Washington Post, "Psychotherapy can solve personal problems — why not national crises?," 7 June 2019 But the problem is far too complex and deep-seated for the government to solve. David French, National Review, "Social-Media Censorship Is the Product of Culture and Commerce," 6 June 2019 The second layer then uses these as building blocks to detect slightly more complex shapes. Timothy B. Lee, Ars Technica, "How computers got shockingly good at recognizing images," 18 Dec. 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

15 Jun 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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