mol·e·cule | \ˈmä-li-ˌkyül \

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

Much like the sun causes skin cancer, the damage from UV rays can cause the creation of destructive molecules within the body, called free radicals, Khan explains. Macaela Mackenzie, Allure, "The Scary Way Blue Light From Your Phone Can Affect Your Eyes and Vision," 6 July 2018 Aliphatic carbon is a term for a class of molecules where carbon atoms are arranged in chains, rather than in a ring. Jason Daley, Smithsonian, "Our Galaxy Is Really Greasy and Smells Like Moth Balls," 28 June 2018 In a piece of white clothing, each detergent wash tops up the supply of fluorescent molecules. Helen Czerski, WSJ, "Behind Sparkling White Uniforms, an Optical Trick," 24 May 2018 Culture is associated with chemistry, and the chemistry of a company is not easily reduced to molecules in a test tube. Neil Senturia,, "Creating a feeling of belonging is critical to your company's success," 25 June 2018 The lack of ozone means that ultraviolet energy can penetrate the atmosphere and bust up water molecules into hydrogen and oxygen. Jeffrey Kluger, Time, "Why Earthlings Are So Obsessed With Mars," 1 May 2018 However, water molecules do get trapped between the fibers and so, when wet, polyester is chilly. Andrew Skurka, Outside Online, "The Definitive Guide to Running in the Rain," 24 Apr. 2018 In addition to oxygen molecules, alien astronomers would look at our atmosphere's levels of nitrogen, carbon dioxide, nitrous oxide, and methane. National Geographic, "Aliens Could Detect Life on Earth. Here's How.," 26 Mar. 2018 The mesh, called a metal-organic framework, contains tiny spaces perfect for grabbing and holding onto water molecules. Nathaniel Scharping, Discover Magazine, "Pulling Water From Thin Air," 3 Jan. 2018

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

18 Oct 2018

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Time Traveler for molecule

The first known use of molecule was in 1701

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More Definitions for molecule



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 \

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 \

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

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to teach someone the beliefs of a group

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