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atomic mass unit
noun
: a unit of mass for expressing masses of atoms, molecules, or nuclear particles equal to ¹/₁₂ the mass of a single atom of the most abundant carbon isotope 12C
called also dalton
Examples of atomic mass unit in a Sentence
Recent Examples on the Web
What’s more, the large compounds are likely fragments of even larger parent molecules that could weigh thousands of atomic mass units, Postberg says.
—National Geographic, 27 June 2018
Previously, Cassini detected lighter, gassy molecules such as methane and ethane, which contain one or two carbon atoms and a smattering of hydrogens; these molecules weigh in at around 15 atomic mass units.
—National Geographic, 27 June 2018
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Word History
First Known Use
circa 1942, in the meaning defined above
Time Traveler
The first known use of atomic mass unit was
circa 1942
Dictionary Entries Near atomic mass unit
Cite this Entry
“Atomic mass unit.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/atomic%20mass%20unit. Accessed 22 Nov. 2024.
Kids Definition
atomic mass unit
noun
: a unit of mass for expressing masses of atoms, molecules, or nuclear particles that is equal to ¹⁄₁₂ of the atomic mass of the most abundant kind of carbon
Medical Definition
atomic mass unit
noun
: a unit of mass for expressing masses of atoms, molecules, or nuclear particles equal to ¹/₁₂ the mass of a single atom of the most abundant carbon isotope 12C
called also dalton
More from Merriam-Webster on atomic mass unit
Nglish: Translation of atomic mass unit for Spanish Speakers
Britannica.com: Encyclopedia article about atomic mass unit
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