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
Scientists from the University of Pennsylvania modified molecules from the fungus — which is officially called Aspergillus flavus — to create a new compound and enhance its cancer-killing properties.
—Khloe Quill, FOXNews.com, 29 June 2025
Different molecules absorb light in different ways, and by analysing these absorption patterns – called spectra – scientists infer what chemicals are likely to be present.
—Oliver Swainston, Space.com, 28 June 2025
The bacteria then produced special enzymes that interacted with the plastic molecule, transforming it into the painkiller ingredient.
—Alex Knapp, Forbes.com, 27 June 2025
Enzymes are also highly specific with each typically acting on a specific molecule or type of action.
—Daryl Austin, USA Today, 27 June 2025
See All Example Sentences for molecule
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Khloe Quill, FOXNews.com, 29 June 2025
Different molecules absorb light in different ways, and by analysing these absorption patterns – called spectra – scientists infer what chemicals are likely to be present.
—Oliver Swainston, Space.com, 28 June 2025
The bacteria then produced special enzymes that interacted with the plastic molecule, transforming it into the painkiller ingredient.
—Alex Knapp, Forbes.com, 27 June 2025
Enzymes are also highly specific with each typically acting on a specific molecule or type of action.
—Daryl Austin, USA Today, 27 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 13 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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