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
Trees then absorb this radioactive isotope, locking a chemical time stamp of the solar storm into their annual growth rings.
—
Jacek Krywko, Scientific American, 10 Apr. 2026
Avalanche will work to build solid-state microfabricated cells that convert alpha particles emitted by radioactive isotopes into electricity (alphavoltaic cells).
—Ameya Paleja, Interesting Engineering, 9 Apr. 2026
Today, this history is etched into a landscape pockmarked with deep craters and atomic lakes, contaminated with radioactive isotopes cesium-137, strontium-90 and plutonium-239 that can remain dangerous for thousands of years.
—Magdalena Stawkowski, The Conversation, 8 Apr. 2026
In the coming days, scientists will further analyze the samples' mineral chemistry, oxygen isotopes and surface features and use that data to submit an official meteorite classification to the Meteoritical Society, an international organization that promotes planetary science, Fries said.
—Maliya Ellis, Houston Chronicle, 5 Apr. 2026
See All Example Sentences for isotope
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Jacek Krywko, Scientific American, 10 Apr. 2026
Avalanche will work to build solid-state microfabricated cells that convert alpha particles emitted by radioactive isotopes into electricity (alphavoltaic cells).
—Ameya Paleja, Interesting Engineering, 9 Apr. 2026
Today, this history is etched into a landscape pockmarked with deep craters and atomic lakes, contaminated with radioactive isotopes cesium-137, strontium-90 and plutonium-239 that can remain dangerous for thousands of years.
—Magdalena Stawkowski, The Conversation, 8 Apr. 2026
In the coming days, scientists will further analyze the samples' mineral chemistry, oxygen isotopes and surface features and use that data to submit an official meteorite classification to the Meteoritical Society, an international organization that promotes planetary science, Fries said.
—Maliya Ellis, Houston Chronicle, 5 Apr. 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 Apr. 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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