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 The two teens are charged in the fatal shooting of 19-year-old Domingo Paco-Camacho and robbery of 17-year-old Kevin Daniel Pano-Galvez at an apartment complex on Buford Highway, officials said. Henri Hollis, ajc, "2 teens arrested, charged with murder in Brookhaven shooting," 7 Apr. 2021 And on Wednesday, police said five people were shot at an apartment complex on Congress Street in Congress Heights. Washington Post, "Spate of fatal shootings pushes up D.C.’s homicide count," 5 Apr. 2021 About 20 residents were displaced by a Monday morning fire that broke out at an Orlando apartment complex. Joe Mario Pedersen, orlandosentinel.com, "20 residents displaced after fire in Orlando apartment complex: report," 5 Apr. 2021 The minute-and-a-half-long surveillance footage takes place at an apartment complex in North Hollywood where Saweetie lived. Natalie Morin, refinery29.com, "Saweetie & Quavo Speak Out About Elevator Physical Altercation Caught On Video," 5 Apr. 2021 The tow truck then crashed into a stand of palm trees outside an apartment complex, and the driver allegedly got out and ran away. Alex Riggins, San Diego Union-Tribune, "El Cajon man dies in hospital day after hit-run crash involving tow truck," 2 Apr. 2021 The suspect, Dejywan Floyd, 29, of Lumberton, was arrested shortly after 12:30 a.m. Thursday at an apartment complex in Lumberton. Phil Helsel, NBC News, "North Carolina man charged with murder in road rage shooting that killed mom of six," 2 Apr. 2021 The video, obtained by TMZ, is from an apartment complex in North Hollywood where Saweetie was reportedly renting last year. Zoe Haylock, Vulture, "Quavo Pushes Saweetie in Leaked Elevator Footage From 2020," 1 Apr. 2021 They were later taken into custody at an apartment complex. Carol Robinson | Crobinson@al.com, al, "Shot fired during fight inside Alabama high school cafeteria," 1 Apr. 2021 Recent Examples on the Web: Adjective Give him time to acclimatize to The League, and to learn Shanahan’s complex system. Scott Ostler, San Francisco Chronicle, "49ers QB tandem: Why Justin Fields, Jimmy Garoppolo would make sense together," 26 Mar. 2021 But when supply slows or stops, the company’s involvement adds another layer to an already complex system of vaccine manufacturers, the federal government and the state, each of which affects the flow of doses into San Diego County. San Diego Union-Tribune, "After discussions and delays, San Diego joins Blue Shield’s statewide vaccine program," 20 Mar. 2021 Given Kyle Shanahan’s complex system in San Francisco, that’s magnified further. Vincent Frank, Forbes, "Deshaun Watson Allegations Narrow Down San Francisco 49ers Quarterback Options," 19 Mar. 2021 But those seeking citizenship through naturalization must navigate a complex system that includes the U.S. Citizen and Immigration Services civics test — more commonly referred to as the citizenship test. San Antonio Express-News, "Express Briefing: S.A. is the only big Texas city with no vaccine registry. Here's why.," 17 Mar. 2021 The department’s phone lines remain jammed with calls from people seeking information about the complex system of jobless benefits. Mike Rogoway | The Oregonian/oregonlive, oregonlive, "Oregon says it will pay expanded jobless benefits ‘without delay for most people’," 17 Mar. 2021 But those seeking citizenship through naturalization must navigate a complex system that includes the U.S. Citizen and Immigration Services civics test — more commonly referred to as the citizenship test. Hearst Television, Chron, "Can you pass the U.S. Citizenship test? Take it now," 16 Mar. 2021 Each network is its own complex system with its own emergent behavior. Kelsey Houston-edwards, Scientific American, "The Mathematics of How Connections Become Global," 16 Mar. 2021 The Baker administration has been criticized for what many have found to be a complex online sign-up system that is only available to those who have the time and resources to navigate it. Amanda Kaufman, BostonGlobe.com, "What to know about the state’s new preregistration system for COVID-19 vaccine appointments," 10 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.

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

10 Apr 2021

Cite this Entry

“Complex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/complex. Accessed 11 Apr. 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

The Exceptions Quiz III

  • one green toy robot amidst many red toy robots
  • Which of these words does not mean "nonsense"?
True or False

Test your knowledge - and maybe learn something along the way.

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!