com·​plex·​i·​ty | \kəm-ˈplek-sə-tē, käm-\
plural complexities

Definition of complexity 

1 : something complex the complexities of the murder trial

2 : the quality or state of being complex the complexity of the contract

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Examples of complexity in a Sentence

He was impressed by the complexity of the music. The diagram illustrates the complexity of the cell's structure. He doesn't grasp the complexity of the situation.
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Recent Examples on the Web

The skin—which often features many different types of cladding—and the roof are, due to their complexity, more prone to vulnerabilities, such as leaks. Kate Wagner, Curbed, "Building houses that grow with us," 14 Nov. 2018 In addition to the severity of the danger, the breach is impressive for its logistical complexity, requiring top secret coordination between a Chinese military unit and factories were the chips could be installed. Eric Limer, Popular Mechanics, "Tiny Chinese Microchips Reportedly Found Hidden in Amazon, Apple Servers," 4 Oct. 2018 The deceptively simple plan, which looks from the south like a long porch beneath a very flat roof, delivers surprising complexity within. Julie V. Iovine, WSJ, "A Buoyant Building for Looking and Learning," 12 Nov. 2018 But the possibilities that present themselves across both boards quickly create some chewy complexity. Owen Duffy, Ars Technica, "Essen 2018: The best board games from the biggest board game con," 3 Nov. 2018 Planets transiting this area help us understand the underbelly of any situation and serve as a reminder of life’s complexities. Aliza Kelly Faragher, Allure, "The 12 Astrological Houses: Interpreting Your Birth Chart Beyond the Zodiac," 6 Oct. 2018 Because of these complexities, professional installations can sometimes triple the cost of a generator. David Agrell, Popular Mechanics, "Should You Buy a Standby Generator?," 11 Sep. 2018 The entire trajectory of The Good Place is built on Eleanor’s revelation that good people can do bad things (and vice versa), while Crazy Ex Girlfriend sets its main character’s complications and complexities to song. Anne T. Donahue, Marie Claire, "Even If You Hated Skyler White on Breaking Bad, She Changed TV Forever," 9 Aug. 2018 Part of the challenge in figuring out how to think about space conflict is the sheer complexity of the orbital environment—an arena that has long belonged to nation-states, but that is increasingly becoming a domain of commerce and tourism. Garrett M. Graff, WIRED, "The New Arms Race Threatening to Explode in Space," 26 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'complexity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of complexity

1661, in the meaning defined at sense 1

History and Etymology for complexity

see complex entry 2

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Last Updated

5 Dec 2018

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Time Traveler for complexity

The first known use of complexity was in 1661

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More Definitions for complexity



English Language Learners Definition of complexity

: the quality or state of not being simple : the quality or state of being complex

: a part of something that is complicated or hard to understand


com·​plex·​i·​ty | \kəm-ˈplek-sə-tē \
plural complexities

Kids Definition of complexity

1 : the quality or condition of being difficult to understand or of lacking simplicity the complexity of a problem

2 : something difficult to understand or lacking simplicity the complexities of business

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Comments on complexity

What made you want to look up complexity? Please tell us where you read or heard it (including the quote, if possible).


to make faulty or ineffective

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