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
Uranium needs to be concentrated, or enriched, into the isotope uranium 235 in order to serve as either nuclear reactor fuel or material for nuclear weapons.
—
Dan Vergano, Scientific American, 2 Mar. 2026
Any nearby supernova would likely also have injected lots of the radioactive isotope iron-60.
—James Dinneen, Quanta Magazine, 2 Mar. 2026
This data is affirmed by an isotope analysis, which showed that the plague victims grew up in different places.
—Durrie Bouscaren, NPR, 28 Feb. 2026
The strikes last year did not target the Tehran Research Reactor, which requires 20% enrichment protocols to build radio isotopes to produce medicine and conduct agricultural research, the officials said.
—CBS News, 28 Feb. 2026
See All Example Sentences for isotope
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Dan Vergano, Scientific American, 2 Mar. 2026
Any nearby supernova would likely also have injected lots of the radioactive isotope iron-60.
—James Dinneen, Quanta Magazine, 2 Mar. 2026
This data is affirmed by an isotope analysis, which showed that the plague victims grew up in different places.
—Durrie Bouscaren, NPR, 28 Feb. 2026
The strikes last year did not target the Tehran Research Reactor, which requires 20% enrichment protocols to build radio isotopes to produce medicine and conduct agricultural research, the officials said.
—CBS News, 28 Feb. 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 11 Mar. 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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