complex

1 of 3

noun

com·​plex ˈkäm-ˌpleks How to pronounce complex (audio)
1
: a whole made up of complicated or interrelated parts
a complex of welfare programs
the military-industrial complex
2
a
: 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

2 of 3

adjective

com·​plex käm-ˈpleks How to pronounce complex (audio)
kəm-ˈpleks,
ˈkäm-ˌpleks
1
a
: 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
complexly adverb
complexness noun

complex

3 of 3

verb

com·​plex käm-ˈpleks How to pronounce complex (audio)
kəm-ˈpleks,
ˈkäm-ˌpleks
complexed; complexing; complexes

transitive verb

1
: to make complex or into a complex
2
complexation noun

Did you know?

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”).

Choose the Right Synonym for complex

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

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
Recent Examples on the Web
Noun
Video footage from the Crocus City Hall showed the vast complex, which is home to both a music hall and shopping center, on fire with smoke billowing into the air. Lauren Said-Moorhouse, CNN, 23 Mar. 2024 However, Jiménez was forced out in 1958, and successive governments lost interest in the complex, which remained unfinished. John Otis, NPR, 23 Mar. 2024 Developers called the complex of warehouses and industrial space an economic game-changer for South Miami-Dade that would bring 7,000 jobs to an area where many people must commute north for work. Douglas Hanks, Miami Herald, 22 Mar. 2024 Donington Park is a fun circuit with changing gradients, flowing complexes of corners, and plenty of run-off. Tim Pitt, Robb Report, 22 Mar. 2024 Rancho Palos Verdes officials are preparing to close a section of Palos Verdes Drive South for repairs after the two-lane roadway suffered damage from an accelerating landslide complex that continues to wreak havoc on the coastal city. Jireh Deng, Los Angeles Times, 22 Mar. 2024 Tickets to the theater complex are significantly cheaper compared to indoor movie theater prices. Brianna Taylor, Sacramento Bee, 22 Mar. 2024 This is not the first time Israeli forces have raided the Al-Shifa medical complex during the war with Hamas. Mary Kekatos, ABC News, 21 Mar. 2024 Despite the shifting occupancies, all of the office buildings in the Coleman Highline complex are producing rental income since they are all being leased. George Avalos, The Mercury News, 20 Mar. 2024
Adjective
One such instance recounts Lucarelli’s encounter with discrepancies in cash deposits during his tenure, unraveling a complex web of deceit and maleficence within the company’s ranks. Hilary Tetenbaum, USA TODAY, 23 Mar. 2024 The experience also taught her valuable lessons about navigating complex political systems. Ellen Wexler, Smithsonian Magazine, 22 Mar. 2024 Miners compete to be the first to solve complex problems that are rewarded with crypto; because the chances of solving it first are infinitesimally small, miners have an advantage by using more and faster computers, which translates into intense energy demands. Irina Ivanova, Fortune, 22 Mar. 2024 Drug shortages are an increasing problem in the US and oftentimes happen with older medicines whose prices have fallen because their patents have expired but are still complex to manufacture. Meg Tirrell, CNN, 22 Mar. 2024 That meant many months of varnish removal and complex lime-washing. Howard Walker, Robb Report, 22 Mar. 2024 The way a cloud forms or responds to human intervention will depend on a range of complex, shifting factors — from weather to how particles spread by humans interact with other aerosols already in the air. Justine Calma, The Verge, 21 Mar. 2024 Some people have complex scenarios and can benefit from a professional service. Larry Magid, The Mercury News, 21 Mar. 2024 Today, these tests — which are designed, manufactured, and used in a single laboratory — are more complex and inform around 70% of health care decisions, according to the Centers for Disease Control and Prevention. Annalisa Merelli, STAT, 21 Mar. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'complex.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Noun

borrowed from Latin complexus "embrace, grasp, inclusion" (Late Latin also, "whole, entirety") from complector, complectī "to embrace, grasp, encompass, include" + -tus, suffix of action nouns; (sense 2b (1)) after German Komplex — more at complex entry 2

Adjective

borrowed from Late Latin complexus "composite, connected, intertwined," going back to Latin, past participle of complector, complectī "to embrace, grasp, encompass, include," from com- com- + -plectī, deponent form of plectere "to plait, twine" — more at ply entry 3

Verb

derivative of complex entry 1 or complex entry 2

First Known Use

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

Time Traveler
The first known use of complex was in 1643

Dictionary Entries Near complex

Cite this Entry

“Complex.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/complex. Accessed 28 Mar. 2024.

Kids Definition

complex

1 of 2 noun
com·​plex ˈkäm-ˌpleks How to pronounce complex (audio)
1
: a whole made up of many complicated or related parts
2
: a system of thoughts, feelings, and memories that exist in one's mind but of which one is not aware and which influence one's behavior
3
: a building or group of buildings housing related units
an apartment complex

complex

2 of 2 adjective
com·​plex käm-ˈpleks How to pronounce complex (audio)
kəm-;
ˈkäm-ˌpleks
1
a
: composed of two or more parts
a complex mixture
b
: consisting of a main clause and one or more subordinate clauses
a complex sentence
c
: formed by union of simpler substances
2
: having many parts, details, ideas, or functions often related in a complicated way
a complex problem
a complex machine
complexly adverb

Medical Definition

complex

1 of 3 adjective
com·​plex käm-ˈpleks How to pronounce complex (audio) kəm-ˈ How to pronounce complex (audio)
ˈkäm-ˌ
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

2 of 3 noun
com·​plex ˈkäm-ˌpleks How to pronounce complex (audio)
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

3 of 3 transitive verb
com·​plex käm-ˈpleks How to pronounce complex (audio) kəm-ˈ How to pronounce complex (audio)
ˈkäm-ˌ
1
: to form into a complex
RNA complexed with protein
2

intransitive verb

: to form a complex
hormones which must complex with specific receptors

More from Merriam-Webster on complex

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