: 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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Tree-rings reveal two strong solar proton events in 7176 and 5259 BCE
Advancing Earth and Space Sciences.
—
Sean Mowbray, Discover Magazine, 26 May 2025
This parameter is key for discovering whether such phenomena are made of just protons or heavier atomic nuclei — and, therefore, what produces them.
—Keith Cooper, Space.com, 16 May 2025
Scientists there have found a way to knock three tiny particles called protons out of lead atoms, turning them into gold atoms.
—Doc Louallen, ABC News, 13 May 2025
The gravitational pull of the star's remains would have been strong enough to crush together protons and electrons to form neutrons, meaning a neutron star is mostly made of neutrons.
—Charles Q. Choi, Space.com, 22 May 2025
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Sean Mowbray, Discover Magazine, 26 May 2025
This parameter is key for discovering whether such phenomena are made of just protons or heavier atomic nuclei — and, therefore, what produces them.
—Keith Cooper, Space.com, 16 May 2025
Scientists there have found a way to knock three tiny particles called protons out of lead atoms, turning them into gold atoms.
—Doc Louallen, ABC News, 13 May 2025
The gravitational pull of the star's remains would have been strong enough to crush together protons and electrons to form neutrons, meaning a neutron star is mostly made of neutrons.
—Charles Q. Choi, Space.com, 22 May 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 10 Jun. 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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