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 life sciences sector is increasingly ambitious in its drug development activity, discovering and harnessing new molecules and devising more targeted therapies with implications for clinical trials and in-market safety monitoring.
—Aman Wasan, Forbes.com, 19 Sep. 2025
Scientists tested more than 300 combinations of growth factors, small molecules, and metabolites to develop the cells of Nicobar pigeons, the closest relative to the dodo.
—Reed Albergotti, semafor.com, 19 Sep. 2025
That protection could increase the odds that organic molecules still exist intact here.
—Stefanie Waldek, Space.com, 19 Sep. 2025
Diet sodas and other zero-calorie drinks are a mainstay of the modern diet, thanks to the development of artificial sweeteners whose molecules can't be metabolized by the human body.
—ArsTechnica, 18 Sep. 2025
See All Example Sentences for molecule
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Aman Wasan, Forbes.com, 19 Sep. 2025
Scientists tested more than 300 combinations of growth factors, small molecules, and metabolites to develop the cells of Nicobar pigeons, the closest relative to the dodo.
—Reed Albergotti, semafor.com, 19 Sep. 2025
That protection could increase the odds that organic molecules still exist intact here.
—Stefanie Waldek, Space.com, 19 Sep. 2025
Diet sodas and other zero-calorie drinks are a mainstay of the modern diet, thanks to the development of artificial sweeteners whose molecules can't be metabolized by the human body.
—ArsTechnica, 18 Sep. 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 24 Sep. 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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