molecule

noun

mol·​e·​cule ˈmä-li-ˌkyül How to pronounce molecule (audio)
Synonyms of moleculenext
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
There is a molecule of evidence to support these charges.

Synonyms of molecule

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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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The solvent breaks apart dirt and grease molecules and evaporates quickly to leave windows streak-free. — Mary Marlowe Leverette, The Spruce, 29 Aug. 2026 These receptors normally respond to endorphins, which are naturally occurring signaling molecules, and are activated by opioid drugs. — Encyclopedia Britannica, 28 Aug. 2026 The scientists tracked matter loss by following the movements of molecular hydrogen, one of the most common molecules in protoplanetary disks. — Robert Lea, Space.com, 27 Aug. 2026 Or picture a science lab, where microscopes can autonomously search for a certain type of molecule—all hours of the day, no humans necessary. — Emily Forlini, Fortune, 27 Aug. 2026 See All Example Sentences for molecule

Word History

Etymology

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

First Known Use

1701, in the meaning defined at sense 1

Time Traveler
The first known use of molecule was in 1701

Rhymes for molecule

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Browse Nearby Words

molecular weight
molecule
moled
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Cite this Entry

“Molecule.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecule. Accessed 1 Sep. 2026.

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Kids Definition

molecule

noun
mol·​e·​cule ˈmäl-i-ˌkyü(ə)l How to pronounce molecule (audio)
1
: the smallest particle of a substance having all the characteristics of the substance
a molecule of water
a molecule of oxygen
2
: a very small bit : particle

Medical Definition

molecule

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

Britannica.com: Encyclopedia article about molecule

Last Updated: - Updated example sentences
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