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
Also in her portfolio is a four-bedroom Nashville complex with an adjacent guest house, as well as a seven-bedroom home in LA. Byeleanor Pringle, Fortune, 3 Apr. 2024 The gentle serum instantly smooths and soothes thanks to its namesake triple oat complex, which is clinically proven to lock in moisture for rough, dry skin. Danielle Cohen, Glamour, 3 Apr. 2024 See all Example Sentences for complex 

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 16 Apr. 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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