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
There is a molecule of evidence to support these charges.
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 results showed that the unusual absorption behavior arises from interactions between excitons, which carry energy, and charge-transfer states, where electrons move between molecules.
—
Neetika Walter, Interesting Engineering, 11 Apr. 2026
Since refrigerating people wasn’t a viable treatment, Welsh and the CF Foundation needed chemists to create a small molecule that could replicate what happened in the cold.
—Courtney Crowder, USA Today, 10 Apr. 2026
Chemists refer to this kind of structural switch as photoisomerization, a process in which light changes a molecule’s geometry without breaking it apart.
—Chelsea Haney
april 10, New Atlas, 10 Apr. 2026
Much like having a cold, the subsequent congestion can then block odor molecules from reaching olfactory receptors.
—Andrew Paul, Popular Science, 9 Apr. 2026
See All Example Sentences for molecule
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Neetika Walter, Interesting Engineering, 11 Apr. 2026
Since refrigerating people wasn’t a viable treatment, Welsh and the CF Foundation needed chemists to create a small molecule that could replicate what happened in the cold.
—Courtney Crowder, USA Today, 10 Apr. 2026
Chemists refer to this kind of structural switch as photoisomerization, a process in which light changes a molecule’s geometry without breaking it apart.
—Chelsea Haney
april 10, New Atlas, 10 Apr. 2026
Much like having a cold, the subsequent congestion can then block odor molecules from reaching olfactory receptors.
—Andrew Paul, Popular Science, 9 Apr. 2026
See All Example Sentences for molecule
Cite this Entry
“Molecule.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecule. Accessed 15 Apr. 2026.
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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