polonium
noun
po·lo·ni·um
pə-ˈlō-nē-əm 
: a radioactive metallic element that has similar chemical properties to tellurium and bismuth, is produced mainly from the radioactive decay of neutron-irradiated bismuth, and emits an alpha particle to form an isotope of lead see Chemical Elements Table
Examples of polonium in a Sentence
Recent Examples on the Web
Some other elements in nature with no stable isotope are technetium, polonium, actinium and uranium.
—
Kelling Donald,
The Conversation,
13 Oct. 2025
In the first decade of this century, when Russian spy agencies carried out assassinations abroad, those attacks had an obvious Russian state signature, as when the attackers used polonium, or the military-grade nerve agent Novichok.
—
Andrei Soldatov,
Foreign Affairs,
20 Mar. 2025
Putin also is widely believed to kill off opponents, from the spy Alexander Litvinenko (poisoned with polonium in Britain) to journalistAnna Politkovskaya (killed in an elevator) to opposition leader Alexei Navalny (dead last year in a gulag).
—
Daniel R. Depetris,
Newsweek,
10 Jan. 2025
The double Nobel Prize winner is most famous for her discovery of radioactivity, as well as the radioactive elements radium and polonium.
—
Clara Moskowitz,
Scientific American,
15 Oct. 2024
See All Example Sentences for polonium
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Kelling Donald,
The Conversation,
13 Oct. 2025
In the first decade of this century, when Russian spy agencies carried out assassinations abroad, those attacks had an obvious Russian state signature, as when the attackers used polonium, or the military-grade nerve agent Novichok.
—
Andrei Soldatov,
Foreign Affairs,
20 Mar. 2025
Putin also is widely believed to kill off opponents, from the spy Alexander Litvinenko (poisoned with polonium in Britain) to journalistAnna Politkovskaya (killed in an elevator) to opposition leader Alexei Navalny (dead last year in a gulag).
—
Daniel R. Depetris,
Newsweek,
10 Jan. 2025
The double Nobel Prize winner is most famous for her discovery of radioactivity, as well as the radioactive elements radium and polonium.
—
Clara Moskowitz,
Scientific American,
15 Oct. 2024
See All Example Sentences for polonium
Cite this Entry
“Polonium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/polonium. Accessed 5 Jul. 2026.
Copy CitationKids Definition
polonium
noun
po·lo·ni·um
pə-ˈlō-nē-əm
: a radioactive metallic element that is found in pitchblende and decays to form lead see element
Medical Definition
polonium
noun
po·lo·ni·um
pə-ˈlō-nē-əm
: a radioactive metallic element that is similar chemically to tellurium and bismuth, occurs especially in pitchblende and radium-lead residues, and emits an alpha particle to form an isotope of lead
—symbol Po
see Chemical Elements Table
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