: 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
Recent Examples on the Web
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
See All Example Sentences for proton
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
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 4 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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share