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
Researchers argue this would likely release radioactive particles and isotopes into the atmosphere throughout the flight.
—
Kaif Shaikh, Interesting Engineering, 22 June 2026
The comet contains far more heavy hydrogen—in the form of an isotope called deuterium, which has one neutron and one proton—than any local space rock, a quality that tends to point to colder environs.
—Joseph Howlett, Scientific American, 22 June 2026
The new research is based on the comet's ratio of chemical elements, called isotopes, detected by the James Webb space telescope and the ALMA observatory in Chile.
—CBS News, 22 June 2026
Analysis of zinc isotopes preserved in fossilized shark teeth, published in Nature Communications in 2022, found that when great white sharks and megalodon coexisted during the Pliocene, their diets overlapped significantly, both feeding high up the same food chain on marine mammals.
—Scott Travers, Forbes.com, 20 June 2026
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Kaif Shaikh, Interesting Engineering, 22 June 2026
The comet contains far more heavy hydrogen—in the form of an isotope called deuterium, which has one neutron and one proton—than any local space rock, a quality that tends to point to colder environs.
—Joseph Howlett, Scientific American, 22 June 2026
The new research is based on the comet's ratio of chemical elements, called isotopes, detected by the James Webb space telescope and the ALMA observatory in Chile.
—CBS News, 22 June 2026
Analysis of zinc isotopes preserved in fossilized shark teeth, published in Nature Communications in 2022, found that when great white sharks and megalodon coexisted during the Pliocene, their diets overlapped significantly, both feeding high up the same food chain on marine mammals.
—Scott Travers, Forbes.com, 20 June 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 25 Jun. 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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