proton

noun

pro·ton ˈprō-ˌtän

: 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

protonic

prō-ˈtä-nik

adjective

Examples of proton in a Sentence

Recent Examples on the Web

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Others have been far too quiet—producing only one billionth the energy of the proton-proton collisions at CERN’s Large Hadron Collider, the most powerful particle accelerator on Earth. — Joseph Howlett, Scientific American, 31 Aug. 2026 By comparing these to oxygen-proton collisions from the same run as a control, the researchers concluded that there was jet quenching or parton energy loss in these collisions. — Ameya Paleja, Interesting Engineering, 31 Aug. 2026 As the cosmos cooled and expanded, the free-floating quarks and gluons started binding together to create the building blocks of all matter, including all those necessary atomic protons and neutrons. — Andrew Paul, Popular Science, 20 Aug. 2026 In November 2023, Tyman underwent 33 rounds of proton therapy to eliminate remaining cancer cells, and she was declared cancer-free in January 2024. — Vanessa Etienne, PEOPLE, 20 Aug. 2026 See All Example Sentences for proton

Word History

Etymology

Greek prōton, neuter of prōtos first — more at proto-

First Known Use

1920, in the meaning defined above

Time Traveler

The first known use of proton was in 1920

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Cite this Entry

Style

“Proton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proton. Accessed 1 Sep. 2026.

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Kids 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

protonic

prō-ˈtän-ik

adjective

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

protonic

prō-ˈtän-ik

adjective

proton

noun

Examples of proton in a Sentence

Word History

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proton

noun

Examples of proton in a Sentence

Word History

Phrases Containing proton

Rhymes for proton

Browse Nearby Words

Cite this Entry

Kids Definition

Medical Definition

More from Merriam-Webster on proton

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