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 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 proprietary complex, which has made appearances in other Rodan + Fields products, helps draw moisture into skin with the help of hyaluronic acid. Devon Abelman, Allure, "Rodan + Fields Just Launched a Fun Line of Face Masks For Every Complexion Concern," 15 May 2019 The missile was launched from a field just north of the building complex, with the largest, densest cloud still hovering directly over the field. Kyle Mizokami, Popular Mechanics, "Satellite Startup Accidentally Spots Secret North Korean Missile Test," 7 May 2019 But in the bridal industrial complex, that was impossible. Melissa Kravitz, Glamour, "What I Never Expected About Shopping for a Wedding Dress As a Gay Woman," 2 Apr. 2019 Candles flickered and balloons waved in the wind as family and friends gathered in memory of Eveona Cortez and Elizabeth Juarez, teenage girls gunned down at an apartment complex in Burien one year ago Thursday. Bettina Hansen, The Seattle Times, "Remembering two young lives lost in Burien," 30 Mar. 2019 Despite what Apple might be able to offer in terms of either privacy or exclusive content, though, the company can't avoid the problem that's beginning to loom over the tech-entertainment complex. Eric Limer, Popular Mechanics, "How Many Subscriptions Can You Handle?," 25 Mar. 2019 Metals prices were mixed on Thursday, with the precious complex broadly boosted by the U.S. Federal Reserve’s decision not to raise interest rates further this year. Christopher Alessi, WSJ, "Gold Gets a Boost From Fed’s Dovish Stance," 21 Mar. 2019 The sprawling re-vamp of MTA's rail yards boasts two apartment complexes complete with private entrances and keyless entry for its wealthy owners. House Beautiful, "Everything You Need to Know About Hudson Yards, New York's $25 Billion Neighborhood," 19 Mar. 2019 The president has 58 million Twitter followers and a vast conservative media-industrial complex that will happily amplify his comments. Sean Illing, Vox, "How the media should respond to Trump’s lies: State of the Union edition," 5 Feb. 2019

Recent Examples on the Web: Adjective

With complex dance combinations, executed one eight-count at a time. Mackenzie Wagoner, Vogue, "Happy Birthday, Janet Jackson! How to Get Her Rock-Hard Body in 12 GIFS," 16 May 2019 Go is so complex even a supercomputer can’t calculate good moves by brute force. Avery Thompson, Popular Mechanics, "An AI Beat the Top Humans at a Modern Video Game Thanks to the Power of Teamwork," 16 Apr. 2019 Endometriosis has a notorious reputation as an excruciating, complex condition with a tangle of potential mechanisms that doctors are still attempting to unsnarl. Carolyn L. Todd, SELF, "8 Ways People With Endometriosis Deal With the Pain," 24 Apr. 2019 Wainwright has been working on adapting Lister’s diaries for the screen for over 20 years, and the result of her efforts is a period drama that features complex women onscreen, captured by many brilliant women behind the camera. Jill Gutowitz, Glamour, "Gentleman Jack Is a Period Drama I’ve Been Waiting My Whole Life to See," 22 Apr. 2019 The complex dynamic between Buttigieg and Pence reflects a connection born of political necessity between two men on the cusp of unlikely political and personal paths. Brian Slodysko, The Seattle Times, "Buttigieg, once cordial to Pence, now critical amid campaign," 13 Apr. 2019 There are a few cool new features, such as Windows Sandbox and support for the complex kaomoji emoji. Mark Hachman, PCWorld, "Microsoft's Windows 10 May 2019 Update can be downloaded now: Here's how," 8 Apr. 2019 Building connection long-distance is a complex process, starting with trying to circumvent the Great Firewall of China, a safety net barring danger and dissent, but also possibility and perspective. Shao Xinning, Seventeen, "This Teen Created Her Own Pen Pal Service in Order to Connect Girls Across China," 18 Mar. 2019 Expert analysis points to a more complex, multi-layered series of overlapping trends, with unpredictable results, as opposed to a few strong narratives. Patrick Sisson, Curbed, "The 10 top emerging trends that will shape real estate in 2019," 10 Oct. 2018

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

Statistics for complex

Last Updated

18 May 2019

Look-up Popularity

Time Traveler for complex

The first known use of complex was in 1643

See more words from the same year

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

something valued as if it were money

Get Word of the Day daily email!

Test Your Vocabulary

Time Traveler Quiz: Which Word Came First?

  • time traveler quiz which word came first
  • Which came first?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

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!