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

Example Sentences

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
The three-story complex is tough to miss at 301 Oxmoor Lane, near the Interstate 264 ramp onto Shelbyville Road, and officials behind the project say golfers shouldn't be the only ones looking forward to checking it out. Caleb Stultz, The Courier-Journal, 17 Nov. 2022 The 26-building complex is seaward of other Oceanside residential development, on the sand near the Oceanside harbor. Phil Diehl, San Diego Union-Tribune, 17 Nov. 2022 The complex would include 78 affordable, 18 moderate-income, and 24 market-rate units. John Laidler, BostonGlobe.com, 17 Nov. 2022 The eight-story complex will have 180 apartments — 50 two-bedroom, 103 one-bedroom and 27 studio units. Alixel Cabrera, The Salt Lake Tribune, 16 Nov. 2022 The complex has a boutique hotel, office space, condos and a public area called Broadway Square with dancing fountains, a farmers market, movie nights, concerts, winter ice skating—and a parking deck. Joe Barrett, WSJ, 11 Nov. 2022 At the heart of Steppenwolf’s new complex is The Ensemble Theater, an intimate and state-of-the-art 400-seat theater in the round. Judy Koutsky, Forbes, 10 Nov. 2022 The new complex will also be able to house regional public safety training, and other regional functions are being explored. Steve Smith, Hartford Courant, 9 Nov. 2022 The complex will include a restaurant, tournament facilities, a clubhouse with locker rooms and 39 pickleball courts to accommodate a fast-growing sport that’s a mix of tennis, ping-pong and badminton. Susannah Bryan, Sun Sentinel, 2 Nov. 2022
Adjective
It’s just the end of the observable universe, which could one day expand as space exploration technology grows more complex and powerful. Joshua Hawkins, BGR, 21 Nov. 2022 Our win should be a lesson to anyone who writes off some states as not worth fighting for—or deems some issues too tough or complex and thus, unwinnable. Time, 17 Nov. 2022 La Roche-Posay's formula is formulated with titanium dioxide and zinc oxide, as well as a powerful antioxidant complex and thermal spring water, that feels utterly weightless on skin. Sophie Dweck, Town & Country, 16 Nov. 2022 Imagine the engine of a car with all those complex and connected parts. Bryce Millercolumnist, San Diego Union-Tribune, 16 Nov. 2022 Scheduled for 2024, Artemis II would then be followed by an even more complex and historic mission, Artemis III, which would at last return humans to the lunar surface for the first time since 1972. Nadia Drake, Scientific American, 16 Nov. 2022 Use complex and different passwords for each of your online accounts. Marc Saltzman, USA TODAY, 11 Nov. 2022 That means teasing out which proteins are present in a complex and degraded sample can be difficult. Jo Marchant, Smithsonian Magazine, 10 Nov. 2022 It’s mind-numbingly complex and frankly kind of boring. Abdul El-sayed, The New Republic, 9 Nov. 2022 See More

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.

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 1 Dec. 2022.

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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