molecule

noun

mol·​e·​cule ˈmä-li-ˌkyül How to pronounce molecule (audio)
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
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.
This allows a second drug molecule, one designed with a cancer target on one end and an opposite end that binds with the generic receptor to snap in place. Paul Sisson, San Diego Union-Tribune, 6 July 2025 Here's how: Combating Oxidative Stress Every day, our mouths are exposed to bacteria, toxins and environmental stressors that generate reactive oxygen species (ROS), unstable molecules that damage cells and accelerate the aging process. Ximena Araya-Fischel, Forbes.com, 4 July 2025 And perhaps most importantly, JWST allowed researchers to detect new molecules in the planet that haven’t been detected before, like methane, carbon monoxide, and silicon monoxide. Sara Novak, Discover Magazine, 2 July 2025 Crops belonging to the nightshade family like potatoes, eggplants, and tomatoes produce these bitter-tasting molecules to help ward off predation by fungi, insects, and other animals. New Atlas, 29 June 2025 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

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Cite this Entry

“Molecule.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecule. Accessed 15 Jul. 2025.

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

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