proton

noun

pro·​ton ˈprō-ˌtän How to pronounce proton (audio)
: 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 adjective

Example Sentences

Recent Examples on the Web The core becomes so intensely squeezed that the iron atoms rearrange themselves; the electrons shove inside of protons, turning all of the iron into a giant ball of neutrons. Popular Mechanics, 18 Apr. 2023 To an extent, this is similar to the question of where the mass of a proton is. John Timmer, Ars Technica, 3 Apr. 2023 Alternative fuel made of protons and boron generates no neutrons and produces only harmless helium, but requires a temperature of 3 billion degrees Celsius—200 times the heat of the Sun’s core—to burn. Byscience News Staff, science.org, 2 Mar. 2023 And the third is a radiation storm fueled by accelerating energy particles like protons, elections, and ions. Jon Kelvey, Popular Science, 27 Feb. 2023 It is likely caused by electrons—a by-product of the protons that trigger the typical green aurora—raining onto Earth's magnetic field. Sasha Warren, Scientific American, 1 Oct. 2022 This electrostatic shield guards against proton storms caused by explosions from the sun called coronal mass ejections, and could be deployed only during those events while the ship relies on another system for day-to-day protection. Joe Pappalardo, Popular Mechanics, 8 May 2023 But in 1979, Argonne shut down its proton accelerator, which had been superseded by a much bigger, new one at Fermi National Accelerator Laboratory 50 kilometers away. Byadrian Cho, science.org, 4 May 2023 Strings also appear in the way the strong force acts among quarks, which are the elementary particles that make up a proton. Kevin Hartnett, Quanta Magazine, 18 Apr. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'proton.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

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

Dictionary Entries Near proton

Cite this Entry

“Proton.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/proton. Accessed 29 May. 2023.

Kids Definition

proton

noun
pro·​ton ˈprō-ˌtän How to pronounce proton (audio)
: 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 adjective

Medical Definition

proton

noun
pro·​ton ˈprō-ˌtän How to pronounce proton (audio)
: 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 adjective

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