molecule
noun
mol·e·cule
ˈmä-li-ˌkyül 
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 honesty—
Time
TimeExamples 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
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
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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
Cite this Entry
“Molecule.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecule. Accessed 18 Jul. 2025.
Copy CitationKids Definition
molecule
noun
mol·e·cule
ˈmäl-i-ˌkyü(ə)l
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
: 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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