proton

noun
pro·​ton | \ ˈprō-ˌtän How to pronounce proton (audio) \

Definition of proton

: 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

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Other Words from proton

protonic \ prō-​ˈtä-​nik How to pronounce protonic (audio) \ adjective

Examples of proton in a Sentence

Recent Examples on the Web

For instance, a project called the Karlsruhe Tritium Neutrino (KATRIN) experiment in Germany aims to measure neutrino mass by observing beta decays in which a neutron transforms into a proton by releasing a neutrino and an electron. Clara Moskowitz, Scientific American, "Mysterious Neutrinos Get New Mass Estimate," 26 Aug. 2019 These are constituents of ordinary matter, found in the nuclei of all atoms except the lightest isotope of hydrogen, which is a lone proton. The Economist, "Gravitational astronomy proves its maturity," 22 Aug. 2019 In breaks from his prize-winning work, Rubbia envisioned a 5000-ton detector that would watch for an event expected to be theoretically possible, although vanishingly rare: the decay of the proton. Adrian Cho, Science | AAAS, "Resurrected detector will hunt for some of the strangest particles in the universe," 8 Aug. 2019 This nucleus is made up of even tinier particles called protons and neutrons. Nandita Jayaraj, Quartz India, "Meet Indumathi, the Indian scientist who wants to capture one of the universe’s smallest particles," 27 Aug. 2019 Hundreds of billions of protons and antiprotons were accelerated close to the speed of light and then smashed together. Quanta Magazine, "A Call for Courage as Physicists Confront Collider Dilemma," 7 Aug. 2019 Fermions include electrons and the quarks that are the constituents of protons and neutrons in atomic nuclei. Philip Ball, Scientific American, "Supergravity Snags Super Award: $3-Million Special Breakthrough Prize," 6 Aug. 2019 Atomic nuclei are made of protons and neutrons, known collectively as nucleons. The Economist, "Who did the Maya sacrifice?," 1 Aug. 2019 Physicists use it to predict the likelihood of a neutron decaying into a proton in a radioactive material. Sophia Chen, WIRED, "Why Big Banks Could Soon Jump on the Quantum Bandwagon," 26 July 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'proton.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of proton

1920, in the meaning defined above

History and Etymology for proton

Greek prōton, neuter of prōtos first — more at proto-

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Statistics for proton

Last Updated

14 Oct 2019

Look-up Popularity

Time Traveler for proton

The first known use of proton was in 1920

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More Definitions for proton

proton

noun

English Language Learners Definition of proton

physics : a very small particle of matter that is part of the nucleus of an atom and that has a positive electrical charge

proton

noun
pro·​ton | \ ˈprō-ˌtän How to pronounce proton (audio) \

Kids Definition of proton

: a very small particle that exists in the nucleus of every atom and has a positive charge of electricity

proton

noun
pro·​ton | \ ˈprō-ˌtän How to pronounce proton (audio) \

Medical Definition of proton

: 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

Other Words from proton

protonic \ prō-​ˈtän-​ik How to pronounce protonic (audio) \ adjective

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More from Merriam-Webster on proton

Rhyming Dictionary: Words that rhyme with proton

Spanish Central: Translation of proton

Nglish: Translation of proton for Spanish Speakers

Britannica.com: Encyclopedia article about proton

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