mol·​e·​cule | \ ˈmä-li-ˌkyül How to pronounce molecule (audio) \

Definition of molecule

1 : the smallest particle of a substance that retains all the properties (see property sense 1a) of the substance and is composed of one or more atoms (see atom sense 1a) a molecule of water a molecule of oxygen
2 : a tiny bit : particle a molecule of political honestyTime

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Examples of molecule in a Sentence

There is not a molecule of evidence to support these charges. not a molecule of sense in that girl
Recent Examples on the Web Corynebacteria alters scentless human steroids and other molecules in sweat to produce smelly steroids and sulfur compounds. Paul Vanouse, The Conversation, "An artist’s journey into the science of sweat," 12 Sep. 2019 But that same absorption quality makes water relatively easy to pick out in another planet’s atmosphere, compared to other molecules such as carbon dioxide. Jay Bennett, Smithsonian, "Water Vapor Detected in the Atmosphere of an Exoplanet in the Habitable Zone," 11 Sep. 2019 Nitrites can damage cells and react with other molecules found in food to create an enhanced cancer risk. Alix Wall,, "Some much-loved American Jewish classic foods may increase risk of cancer," 10 July 2019 Researchers at Lawrence Livermore National Laboratory in California and elsewhere had shown that the tiny channels allow water to pass through while blocking other molecules. Robert F. Service, Science | AAAS, "This former playwright aims to turn solar and wind power into gasoline," 3 July 2019 One big player, Cargill Inc., has built on its success with Truvia—a sweetener marketed to consumers that uses stevia-leaf extract—by experimenting with the plant’s other sweet molecules, known as glycosides. Leigh Kamping-carder, WSJ, "This Sugar Substitute Aims to Avoid a Bitter End," 19 Oct. 2018 For example, proteins can be made to hook to other molecules to prolong their activity, or interact in a specific way with a cell's molecular receptors. Bradley J. Fikes,, "La Jolla biotech raises $63 million to make cancer drugs from artificial DNA," 30 Apr. 2018 Those failures led scientists to search for other sirtuin-boosting molecules. Sharon Begley, STAT, "A dietary supplement makes old mice youthful. But will it work in people?," 22 Mar. 2018 Here researchers used reinforcement learning to rapidly design 30,000 new molecules and then narrow them down to six, which were synthesized and further tested in the lab. Jonathan Vanian, Fortune, "Why These Two Innovations In Artificial Intelligence Are So Important: Eye on A.I.," 17 Sep. 2019

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

1701, in the meaning defined at sense 1

History and Etymology for molecule

French molécule, from New Latin molecula, diminutive of Latin moles mass

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Statistics for molecule

Last Updated

1 Nov 2019

Time Traveler for molecule

The first known use of molecule was in 1701

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More Definitions for molecule


How to pronounce molecule (audio)

English Language Learners Definition of molecule

: the smallest possible amount of a particular substance that has all the characteristics of that substance
: a very small amount of something


mol·​e·​cule | \ ˈmä-li-ˌkyül How to pronounce molecule (audio) \

Kids Definition of molecule

: the smallest portion of a substance having the properties of the substance a molecule of water


mol·​e·​cule | \ ˈmäl-i-ˌkyü(ə)l How to pronounce molecule (audio) \

Medical Definition of molecule

: the smallest particle of a substance that retains all the properties of the substance and is composed of one or more atoms

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Comments on molecule

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


to spread as a report or rumor

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