or·​gan·​ism | \ ˈȯr-gə-ˌni-zəm \

Definition of organism 

1 : a complex structure of interdependent and subordinate elements whose relations and properties are largely determined by their function in the whole the nation is not merely the sum of individual citizens at any given time, but it is a living organism, a mystical body … of which the individual is an ephemeral part— Joseph Rossi
2 : an individual constituted to carry on the activities of life by means of parts or organs more or less separate in function but mutually dependent : a living being a multicellular organism

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Other Words from organism

organismic \ ˌȯr-​gə-​ˈniz-​mik \ or less commonly organismal \ ˌȯr-​gə-​ˈniz-​məl \ adjective
organismically \ ˌȯr-​gə-​ˈniz-​mi-​k(ə-​)lē \ adverb

Examples of organism in a Sentence

A human being is a complex organism.

Recent Examples on the Web

Clades are organisms that have evolved from a common ancestor. Chris Ciaccia, Fox News, "'Survival of the laziest' is key to avoiding extinction," 22 Aug. 2018 The classic textbook definition, known as the biological species concept, is a group of organisms that only produce fertile offspring with one another. Bridget Alex, Discover Magazine, "What Defines A Species?," 17 Aug. 2018 Slime molds are among the world’s strangest organisms. Katia Moskvitch, WIRED, "Slime Molds Remember—But Do They Learn?," 14 July 2018 Like Unlike most other disease-causing organisms, plant-parasitic nematodes seldom produce any characteristic symptoms. The Editors, Good Housekeeping, "What Are Nematodes? These Tiny Parasites Can Help — Or Hurt — Your Garden," 1 July 2018 At the same time, there was sequencing of other organisms. Sandy Bauers,, "How high-tech genomics - and simple aspirin - could make your joint replacement better," 17 May 2018 Much more important, there are who-knows-how-many planets circling those stars, and there’s at least a chance that there will be organisms on some of them that could smile for the camera. Jeffrey Kluger, Time, "NASA Is About to Launch the Next Big Step in the Search for Life in Space," 17 Apr. 2018 Living things floating in water are not the only exotic organisms here, 15 miles south of the Arctic Circle. Ned Rozell, Anchorage Daily News, "Finding a steaming oasis, isolated and remote: A look at Alaska’s hot springs," 14 Apr. 2018 The weakest part of the spaceships are the delicate organisms that are inside them. Joe Pappalardo, Popular Mechanics, "Hollywood Has No Idea How Nukes Work," 2 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'organism.' 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 organism

circa 1774, in the meaning defined at sense 1

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Statistics for organism

Last Updated

7 Jan 2019

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Time Traveler for organism

The first known use of organism was circa 1774

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More Definitions for organism



English Language Learners Definition of organism

: an individual living thing

: a system with many parts that depend on each other and work together


or·​gan·​ism | \ ˈȯr-gə-ˌni-zəm \

Kids Definition of organism

: a living thing made up of one or more cells and able to carry on the activities of life (as using energy, growing, or reproducing)


or·​gan·​ism | \ ˈȯr-gə-ˌniz-əm \

Medical Definition of organism 

: an individual constituted to carry on the activities of life by means of organs separate in function but mutually dependent : a living being

Other Words from organism

organismic \ ˌȯr-​gə-​ˈniz-​mik \ also organismal \ -​məl \ adjective
organismically \ -​mi-​k(ə-​)lē \ adverb

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More from Merriam-Webster on organism

Rhyming Dictionary: Words that rhyme with organism

Spanish Central: Translation of organism

Nglish: Translation of organism for Spanish Speakers

Britannica English: Translation of organism for Arabic Speakers

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