: 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 results, obtained at the US Department of Energy’s Thomas Jefferson National Accelerator Facility, provide a new framework for studying the proton’s internal structure.
—
Aman Tripathi, Interesting Engineering, 13 Sep. 2025
Testing particle physics theories, the $8 billion LHC was composed of superconducting magnets that allowed scientists to study subatomic particles including protons, electrons, quarks and photons.
—Lorenzino Estrada, AZCentral.com, 10 Sep. 2025
Regular and purposeful improvements have been a constant factor in the life of LIGO, which consists of two detectors in Washington and Louisiana that can now measure distortions in spacetime that are 1/10,000 the width of a proton, or 700 trillion times smaller than the width of a human hair.
—Robert Lea, Space.com, 10 Sep. 2025
The simplest force that unifies the strong force with the electroweak force is the Georgi-Glashow model, which predicts proton decay on a timescale of around 1030 years, but the proton’s lifetime is already established to be at least 1034 years.
—Ethan Siegel, Big Think, 9 Sep. 2025
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Aman Tripathi, Interesting Engineering, 13 Sep. 2025
Testing particle physics theories, the $8 billion LHC was composed of superconducting magnets that allowed scientists to study subatomic particles including protons, electrons, quarks and photons.
—Lorenzino Estrada, AZCentral.com, 10 Sep. 2025
Regular and purposeful improvements have been a constant factor in the life of LIGO, which consists of two detectors in Washington and Louisiana that can now measure distortions in spacetime that are 1/10,000 the width of a proton, or 700 trillion times smaller than the width of a human hair.
—Robert Lea, Space.com, 10 Sep. 2025
The simplest force that unifies the strong force with the electroweak force is the Georgi-Glashow model, which predicts proton decay on a timescale of around 1030 years, but the proton’s lifetime is already established to be at least 1034 years.
—Ethan Siegel, Big Think, 9 Sep. 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 16 Sep. 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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