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
Recent Examples on the Web
Nitrogen has two stable isotopes: nitrogen-14, the more abundant form, and nitrogen-15, the heavier, less common form.
—
Melanie Beasley, The Conversation, 25 July 2025
Study participants were given a special water to drink that contained isotopes that came out in their urine.
—Maria Godoy, NPR, 24 July 2025
Molten salt will contain the isotopes to reduce risks associated with remaining radioactivity.
—IEEE Spectrum, 7 July 2025
As these glom on, the nucleus becomes an unstable version of itself — a radioactive isotope.
—Jenna Ahart, Quanta Magazine, 2 July 2025
See All Example Sentences for isotope
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Melanie Beasley, The Conversation, 25 July 2025
Study participants were given a special water to drink that contained isotopes that came out in their urine.
—Maria Godoy, NPR, 24 July 2025
Molten salt will contain the isotopes to reduce risks associated with remaining radioactivity.
—IEEE Spectrum, 7 July 2025
As these glom on, the nucleus becomes an unstable version of itself — a radioactive isotope.
—Jenna Ahart, Quanta Magazine, 2 July 2025
See All Example Sentences for isotope
Cite this Entry
“Isotope.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isotope. Accessed 29 Jul. 2025.
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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