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

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 Their research claims that Compass’ molecule—and the method for its production—is far from novel. Wired, 28 July 2022 One protein detected in the secretome caught the researchers’ attention— Secreted Wingless-interacting molecule (swim). William A. Haseltine, Forbes, 11 July 2022 Red blood cells contain a molecule called hemoglobin, which transports oxygen through the body and gives the cells their red color, according to Medical News Today. Nayeli Lomeli, USA TODAY, 26 Sep. 2021 Vaccines are much more difficult to manufacture than a small-molecule pill, such as a generic anti-cholesterol tablet, for instance, which can be reverse-engineered from a single sample and made by combining chemicals. Washington Post, 6 May 2021 The natural alternative For RNA and small-molecule drugs, getting inside cells is a major bottleneck for reaching targets. Amanda B. Keener, Scientific American, 17 June 2020 Plus there isn’t one iota, even one molecule of weird in your purr strategy. Carolyn Hax, Washington Post, 9 July 2022 The secret to what makes BPA such an irreplaceable ingredient in plastics is the same thing that leads to its health risks – the molecule’s chemical structure. Benjamin Elling, The Conversation, 23 June 2022 Rather than working on one specific molecule, the reactions are tracked as working with entire classes of related molecules, such as anything with an alcohol. John Timmer, Ars Technica, 3 May 2022 See More

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.

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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Time Traveler for molecule

Time Traveler

The first known use of molecule was in 1701

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Dictionary Entries Near molecule

molecular weight



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Last Updated

7 Aug 2022

Cite this Entry

“Molecule.” Dictionary, Merriam-Webster, Accessed 15 Aug. 2022.

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More Definitions for molecule


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

More from Merriam-Webster on molecule

Nglish: Translation of molecule for Spanish Speakers

Britannica English: Translation of molecule for Arabic Speakers Encyclopedia article about molecule


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