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

Keep scrolling for more

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
See More
Recent Examples on the Web: Noun Andre Michael Lee, 57, was declared dead after Tucson police officers found Lee with gunshot trauma in an apartment complex and rendered aid to him, according to a statement released Friday by Tucson Police. Peiyu Lin, The Arizona Republic, "Man arrested on suspicion of fatally shooting another man in apartment in downtown Tucson," 1 May 2021 Kind of like the late-night fire that gutted a warehouse in the former Lone Star Brewery complex last weekend. Greg Jefferson, San Antonio Express-News, "Jefferson: Can the Pearl's runaway success be replicated at the old Lone Star Brewery site?," 30 Apr. 2021 The massive museum, housed in complex of renovated factory buildings connected by bridges and corridors, is a pilgrimage destination for contemporary art lovers. BostonGlobe.com, "Three in-state getaways for Mother’s Day," 28 Apr. 2021 Investigators determined Bonno, who lived in the nearby apartment complex, was taking out the trash and may have witnessed his vehicle being burglarized before he was shot. City News Service, San Diego Union-Tribune, "Authorities seeking tips leading to gunman in 1992 homicide," 27 Apr. 2021 During the 2003 outbreak of SARS, a cousin to SARS-CoV-2, the virus circulated through faulty plumbing in a Hong Kong apartment complex, infecting more than 300 residents and killing 33. Miranda Weiss, Smithsonian Magazine, "Sewage Has Stories to Tell. Why Won’t the U.S. Listen?," 26 Apr. 2021 Dear Amy: My husband and I live in a townhouse complex. Amy Dickinson, Detroit Free Press, "Neighbors might be ‘What About Bob-ing’," 24 Apr. 2021 The new arts center will occupy several buildings the gallery restored in the hospital complex on Isla del Rey. WSJ, "An Idyllic Summer Retreat on the Mediterranean’s Most Laid-Back Isle," 24 Apr. 2021 Dear Amy: My husband and I live in a townhouse complex. Amy Dickinson, oregonlive, "Ask Amy: Overly chummy new neighbors need a lesson in boundaries, and quickly," 24 Apr. 2021 Recent Examples on the Web: Adjective With just under 18,000 police departments across the country, policing is extremely complex. Noah Robertson, The Christian Science Monitor, "Policing has changed over the last year. Here’s how.," 30 Apr. 2021 The logistics necessary to bring this off have been complex — not only to adapt to an unaccustomed space, but on account of Covid protocols, which in the Bay Area have been among the strictest in the country. New York Times, "Rossini at the Drive-In, as San Francisco Opera Returns," 30 Apr. 2021 The reasons for this are complex, but Abiad says right now the biggest challenge to vaccination programs in Asia is the supply of doses. Amy Gunia, Time, "Asia's Economies Are Set to Rebound From COVID-19 Faster Than the U.S. or Europe—If They Can Step Up Vaccine Rollouts," 28 Apr. 2021 Doing so across several cloud platforms and data centers is complex and can also result in a fragmented security ecosystem. Pritesh Parekh, Forbes, "Adjusting To The New Norm: How Remote Work Impacts IT Security," 28 Apr. 2021 Panel member and President and CEO of March of Dimes, Stacey D. Stewart believes solutions to this crisis are equally as complex and require collaboration and partnerships like this one to make a real impact. Noel Cody, Essence, "First Steps Toward Equitable Healthcare," 28 Apr. 2021 Still, the reality of America's modern political coalitions is increasingly complex. Steve Peoples, Star Tribune, "Analysis: A reckoning on racism? Not for many leaders of GOP," 26 Apr. 2021 Alzheimer’s and other neurological diseases of aging are complex and can have many causes. Daniela Kaufer, Scientific American, "Damage to a Protective Shield around the Brain May Lead to Alzheimer’s and Other Diseases," 23 Apr. 2021 In a 58-page report issued last month, the commission confirmed that the song was first performed at the minstrel show -- likely by white performers in blackface -- but concluded that the song's history was complex. David Williams, CNN, "University of Texas band members will be required to play 'The Eyes of Texas' or join a different band," 23 Apr. 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.

See More

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

Keep scrolling for more

Learn More about complex

Time Traveler for complex

Time Traveler

The first known use of complex was in 1643

See more words from the same year

Statistics for complex

Last Updated

4 May 2021

Cite this Entry

“Complex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/complex. Accessed 8 May. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

Keep scrolling for more

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

Keep scrolling for more

Comments on complex

What made you want to look up complex? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

Test Your Vocabulary

Star Wars Words Quiz

  • cu jedi training
  • The bounty portion of bounty hunters (such as Boba Fett) comes from a Latin word meaning
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
 AlphaBear 2

Spell words. Make bears.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!