: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with the neutron is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673 × 10−27 kilogram
Examples of proton in a Sentence
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That tells researchers that dark matter can't be made of atoms like everyday matter is, because the particles that comprise atoms — electrons, protons, and neutrons — do interact with light.
—
Robert Lea, Space.com, 28 Feb. 2025
Doctors there, working in conjunction with a team an hour’s drive away at Beaumont Hospital in Royal Oak, drew up an initial treatment plan of chemotherapy and proton therapy.
—Rachel Clarke, CNN, 25 Feb. 2025
For context, the most powerful particle accelerator on Earth, the Large Hadron Collider, accelerates protons to an energy of 7 Tera-electronVolts (TeV).
—John Timmer, Ars Technica, 12 Feb. 2025
Scientists believe that the inner radiation belt, peaking about 621 miles (1000 kilometers) from Earth, is composed of electrons and high-energy protons and is relatively stable over time.
—Lauren Blum, The Conversation, 5 Feb. 2025
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Robert Lea, Space.com, 28 Feb. 2025
Doctors there, working in conjunction with a team an hour’s drive away at Beaumont Hospital in Royal Oak, drew up an initial treatment plan of chemotherapy and proton therapy.
—Rachel Clarke, CNN, 25 Feb. 2025
For context, the most powerful particle accelerator on Earth, the Large Hadron Collider, accelerates protons to an energy of 7 Tera-electronVolts (TeV).
—John Timmer, Ars Technica, 12 Feb. 2025
Scientists believe that the inner radiation belt, peaking about 621 miles (1000 kilometers) from Earth, is composed of electrons and high-energy protons and is relatively stable over time.
—Lauren Blum, The Conversation, 5 Feb. 2025
See All Example Sentences for proton
Cite this Entry
“Proton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proton. Accessed 9 Mar. 2025.
Copy CitationKids Definition
proton
noun
pro·ton
ˈprō-ˌtän 
: an atomic particle that occurs in the nucleus of every atom and carries a positive charge equal in size to the negative charge of an electron
Medical Definition
proton
noun
pro·ton
ˈprō-ˌtän
: an elementary particle that is identical with the nucleus of the hydrogen atom, that along with neutrons is a constituent of all other atomic nuclei, that carries a positive charge numerically equal to the charge of an electron, and that has a mass of 1.673×10−24 gram
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