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
The researchers then conducted a randomized clinical trial in humans, in which half of the participants received the NVG-291 drug, which contained a repair molecule to improve nervous system function.
—Angelica Stabile, FOXNews.com, 3 Oct. 2025
Within those grains, Khawaja and his team found not just frozen water, but the same organic molecules observed in the E-ring.
—Eric Lagatta, USA Today, 3 Oct. 2025
Massive volumes of ambient air move through a system containing a chemical agent that selectively binds to CO2 molecules.
—Tejasri Gururaj, Interesting Engineering, 3 Oct. 2025
But the helicase acts like a brake, causing the molecule to go through with a ratcheting motion, one base at a time, at a still-lively rate of about 400 bases per second.
—IEEE Spectrum, 2 Oct. 2025
See All Example Sentences for molecule
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Angelica Stabile, FOXNews.com, 3 Oct. 2025
Within those grains, Khawaja and his team found not just frozen water, but the same organic molecules observed in the E-ring.
—Eric Lagatta, USA Today, 3 Oct. 2025
Massive volumes of ambient air move through a system containing a chemical agent that selectively binds to CO2 molecules.
—Tejasri Gururaj, Interesting Engineering, 3 Oct. 2025
But the helicase acts like a brake, causing the molecule to go through with a ratcheting motion, one base at a time, at a still-lively rate of about 400 bases per second.
—IEEE Spectrum, 2 Oct. 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 5 Oct. 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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