isotope
noun
iso·tope
ˈī-sə-ˌtōp 
1
: any of two or more species of atoms of a chemical element with the same atomic number and nearly identical chemical behavior but with differing atomic mass or mass number and different physical properties
2
: nuclide
Examples of isotope in a Sentence
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In the new work, Milton and her colleagues examined the ratio of different isotopes—forms of atoms with differing numbers of uncharged neutrons in their nucleus—of carbon, nitrogen and sulfur in maize cobs archaeologists had uncovered from the Chincha Valley.
—
Meghan Bartels, Scientific American, 11 Feb. 2026
While working on Copernicus, York was the first researcher to find an isotope of hydrogen known as deuterium inside these clouds.
—Bob Goldsborough, Chicago Tribune, 7 Feb. 2026
Innovative technologies and techniques at Argonne, including collinear laser spectroscopy, enable accurate studies of rare isotopes.
—Prabhat Ranjan Mishra, Interesting Engineering, 2 Feb. 2026
The scientists found that the ratio of the heavier potassium isotope, potassium-41, relative to potassium-39 is greater in the samples from the South Pole–Aitken Basin than in samples from the near side collected by the Apollo missions and lunar meteorites.
—Keith Cooper, Space.com, 23 Jan. 2026
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Meghan Bartels, Scientific American, 11 Feb. 2026
While working on Copernicus, York was the first researcher to find an isotope of hydrogen known as deuterium inside these clouds.
—Bob Goldsborough, Chicago Tribune, 7 Feb. 2026
Innovative technologies and techniques at Argonne, including collinear laser spectroscopy, enable accurate studies of rare isotopes.
—Prabhat Ranjan Mishra, Interesting Engineering, 2 Feb. 2026
The scientists found that the ratio of the heavier potassium isotope, potassium-41, relative to potassium-39 is greater in the samples from the South Pole–Aitken Basin than in samples from the near side collected by the Apollo missions and lunar meteorites.
—Keith Cooper, Space.com, 23 Jan. 2026
See All Example Sentences for isotope
Cite this Entry
“Isotope.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isotope. Accessed 14 Feb. 2026.
Copy CitationKids Definition
isotope
noun
iso·tope
ˈī-sə-ˌtōp
: any of the forms of an element that differ in the number of neutrons in an atom
Medical Definition
isotope
noun
iso·tope
ˈī-sə-ˌtōp
1
: any of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with differing atomic mass or mass number and different physical properties
2
: nuclide
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