proton

American  

[proh-ton] / ˈproʊ tɒn /

noun

Physics, Chemistry.

1. a positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of ½, and a mass of 1.673 × 10 -27 kg. P

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proton British  

/ ˈprəʊtɒn /

noun

1. a stable, positively charged elementary particle, found in atomic nuclei in numbers equal to the atomic number of the element. It is a baryon with a charge of 1.602176462 × 10 ^–19 coulomb, a rest mass of 1.672 62159 × 10 ^–27 kilogram, and spin 1/ 2

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proton Scientific  

/ prō′tŏn′ /

1. A stable subatomic particle in the baryon family having a mass of 1.672 × 10 ^{- 24} grams (1,836 times that of the electron) and a positive electric charge of approximately 1.602 × 10 ^{- 19} coulombs. Protons make up part of the nucleus of all atoms except hydrogen, whose nucleus consists of a single proton. In neutral atoms, the number of protons is the same as the number of electrons. In positively charged atoms, the number of protons is greater than the number of electrons, and in negatively charged atoms electrons outnumber protons. Protons are believed to be composed of two up quarks and one down quark.

2. See Table at subatomic particle

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proton Cultural  

1. An elementary particle with a positive charge, found in the nucleus of an atom.

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Discover More

Protons and neutrons make up most of an atom's mass.

A proton is over a thousand times heavier than an electron.

Other Word Forms

• protonic adjective

Etymology

Origin of proton

Term first suggested in 1920 by English physicist Ernest Rutherford as noun use of Greek prôton, neuter of prôtos “first,” the proton being the constituent of hydrogen nuclei, and formed on the analogy of electron; first, electron

Compare meaning

How does proton compare to similar and commonly confused words? Explore the most common comparisons:

• proton vs. electron

Example Sentences

A trial using proton beams to try to treat a cancer caused mainly by exposure to asbestos has been described as offering "realistic hope" to patients.

From BBC

In this region, the number of protons and neutrons is equal.

From Science Daily

In this picture, a single particle moves through a sea of fermions such as electrons, protons, or neutrons and constantly interacts with those around it.

From Science Daily

People with the "pancreatic-predominant" pattern showed a proton density fat fraction -- an MRI marker that provides a precise estimation of fat concentration in tissue -- of about 30 percent in the pancreas.

From Science Daily

She says one of the early clues that something was seriously amiss came when she took him to the US for specialist proton treatment.

From BBC