: 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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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
Measurements made while the system was in transit suggest that the whole process occurred losslessly, meaning that not a single proton escaped during the entire transport.
—John Timmer, ArsTechnica, 19 May 2025
In the near-collisions, some lead atoms lost three of their protons, turning them into gold atoms.
—George Petras, USA Today, 17 May 2025
In rare cases, three protons are knocked out of a lead nucleus, leaving behind gold in its place.
—Melissa Fleur Afshar, MSNBC Newsweek, 9 May 2025
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Charles Q. Choi, Space.com, 22 May 2025
Measurements made while the system was in transit suggest that the whole process occurred losslessly, meaning that not a single proton escaped during the entire transport.
—John Timmer, ArsTechnica, 19 May 2025
In the near-collisions, some lead atoms lost three of their protons, turning them into gold atoms.
—George Petras, USA Today, 17 May 2025
In rare cases, three protons are knocked out of a lead nucleus, leaving behind gold in its place.
—Melissa Fleur Afshar, MSNBC Newsweek, 9 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 2 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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