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

Keep scrolling for more

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
See More
Recent Examples on the Web: Noun The complex in Forney is just Harris’ latest endeavor. Dom Difurio, Dallas News, "Dallas’ Fran Harris follows up UT, WNBA and ESPN fame with a $13 million youth sports plan for Forney," 2 Jan. 2020 The proposed Terra complex is near a variety of companies that are home to various distribution, storage and light manufacturing businesses. David Lyons, sun-sentinel.com, "Nearly 1,400 apartments to rise near planned American Dream Miami, the nation’s biggest mall," 12 Dec. 2019 The apartment complex is directly across the street from Hudson elementary school. Carol Robinson | Crobinson@al.com, al, "‘Such a beautiful kid’: Teammates, coaches, family honor 5-year-old Birmingham homicide victim," 12 Dec. 2019 Officials say Ibanez went to a 23-year-old woman’s house in the Huntington Green Apartments complex on Kerwin Road about 1:10 p.m. Friday. Jane Morice | Jmorice@cleveland.com, cleveland, "University Heights police seek help to find Warrensville Heights woman charged with stabbing woman, setting fire to apartment," 23 Dec. 2019 Police found Cobb dead inside the complex, Thompson told reporters. Dakin Andone, CNN, "1 person killed in a shooting at North Carolina municipal building. The shooter is also dead," 20 Dec. 2019 In fact, the complexes are falling apart and a woman was killed in the weeks before his visit. Molly Parker, ProPublica, "My Home Is a Place That Feels Safe. For Too Many Families, That’s Not the Case.," 20 Dec. 2019 The 2020 preseason will mark FC Cincinnati's fifth consecutive year at the expansive IMG complex. Pat Brennan, Cincinnati.com, "FC Cincinnati set for up to 7 exhibition matches in 2020 preseason," 20 Dec. 2019 Meanwhile, there are ideas for keeping some revenue coming in from the Coliseum complex. Phil Matier, SFChronicle.com, "As Raiders run off to Las Vegas, they leave behind $65 million in debt in Oakland," 18 Dec. 2019 Recent Examples on the Web: Adjective Trench networks were incredibly complex, encompassing separate frontline, secondary support, communication, food and latrine trenches. Meilan Solly, Smithsonian, "The True History Behind the ‘1917’ Movie," 20 Dec. 2019 With enough of these working together, the entire network has the power to solve more complex problems, even though individual layers of the neural network may only be equipped to complete one kind of equation. Courtney Linder, Popular Mechanics, "Facebook's Neural Net Can Solve This Differential Equation in One Second," 18 Dec. 2019 Rough sleeping is a complex problem, in that it is associated with relationship breakdown and addiction. The Economist, "No crib for a bed On any one winter night, around 5,000 people in Britain sleep rough," 18 Dec. 2019 Too often, the solution is too-simplistic recommendations for immensely complex problems. Stephanie Mcclellan, Quartz, "Women’s health is about more than gynecology," 9 Dec. 2019 More than 22 years after Diana’s tragic death in Paris, people are still inspired by her to tackle often complex problems in their areas in her name. Simon Perry, PEOPLE.com, "What Prince William Told Young People Honored in the Name Of His Late Mother, Princess Diana," 27 Nov. 2019 Computer experts had worked tirelessly for years to fix complex problems. Peter Hartlaub, SFChronicle.com, "My Y2K Story: In San Francisco, death took a holiday on 12/31/1999," 31 Oct. 2019 As of January 2019, Idaho’s Katie Beckett program covers about 2700 children, who are among the nation’s most vulnerable, with complex medical needs or long-term disabilities. Lexi Churchill, ProPublica, "The Trump Administration Cracked Down on Medicaid. Kids Lost Insurance.," 31 Oct. 2019 This is yet another instance where a controller's intimate familiarity with spacecraft systems allowed them to quickly find the root cause of a complex issue and save a mission from a premature end. Lee Hutchinson, Ars Technica, "Apollo Flight Controller 101: Every console explained," 24 Dec. 2019

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

12 Jan 2020

Cite this Entry

“Complex.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/complexness. Accessed 23 January 2020.

Keep scrolling for more

More Definitions for complex

complex

noun
How to pronounce complex (audio)

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
How to pronounce complex (audio)

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
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

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

out of the ordinary or unreasonable

Get Word of the Day daily email!

Test Your Vocabulary

Intact Latin Quiz

  • roman tablet
  • What did focus mean in Latin?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Add Diction

Test Your Knowledge - and learn some interesting things along the way.

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!