electron

American  

[ih-lek-tron] / ɪˈlɛk trɒn /

noun

1. Also called negatron.  Physics, Chemistry. an elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 × 10 −19 coulombs, a mass of 9.108 × 10 −31 kilograms, and spin of ½, and existing independently or as the component outside the nucleus of an atom.

2. Electricity. a unit of charge equal to the charge on one electron.

---

electron British  

/ ɪˈlɛktrɒn /

noun

1. a stable elementary particle present in all atoms, orbiting the nucleus in numbers equal to the atomic number of the element in the neutral atom; a lepton with a negative charge of 1.602 176 462 × 10 ^–19 coulomb, a rest mass of 9.109 381 88 × 10 ^–31 kilogram, a radius of 2.817 940 285 × 10 ^–15 metre, and a spin of 1/ 2

---

electron Scientific  

/ ĭ-lĕk′trŏn′ /

1. A stable elementary particle in the lepton family having a mass at rest of 9.107 × 10 ^{- 28} grams and a negative electric charge of approximately 1.602 × 10 ^{- 19} coulombs. Electrons orbit about the positively charged nuclei of atoms in distinct orbitals of different energy levels, called shells. Electrons are the primary charge carriers in electric current.

2. Compare positron See also electromagnetism elementary particle ion See Table at subatomic particle

3. A positron or a negatron.

---

electron Cultural  

1. An elementary particle with a negative charge and a very small mass. Electrons are normally found in orbits around the nucleus of an atom. The chemical reactions that an atom undergoes depend primarily on the electrons in the outermost orbits (the valence electrons).

---

Discover More

The movement of large numbers of electrons through conductors constitutes an electric current.

Etymology

Origin of electron

Term first suggested in 1891 by Irish physicist G. J. Stoney (1826–1911); electr(ic) + -on (from the names of charged particles, as ion, cation, anion ) with perhaps accidental allusion to Greek ḗlektron amber ( electric )

Compare meaning

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

• proton vs. electron

Explanation

If you take chemistry, you will learn about electrons. Electrons are the smallest of the particles that make up an atom, and they carry a negative charge. The number of protons and electrons is equal in a neutral atom. The hydrogen atom, for example, has just one electron and one proton. The uranium atom, on the other hand, has 92 protons, and therefore, 92 electrons. An electron is so small that it cannot be seen with the naked eye, but neither can the atom itself.

Example Sentences

Rocket Lab investors geek out over the company’s signature aesthetic, from its sleek black carbon-fiber Electron rockets to a custom-built mission-control center designed with pitch-black walls and crimson LED lighting.

From MarketWatch • Jun. 10, 2026

Chip-related stocks led gains, with Tokyo Electron rising 13% and Screen Holdings climbing 18%.

From The Wall Street Journal • Jun. 3, 2026

Electron interactions play a major role in determining properties such as magnetism and chemical bonding.

From Science Daily • May 29, 2026

Companies like semiconductor equipment maker Tokyo Electron and silicon wafer giant Shin-Etsu Chemical have kept stock indexes buoyant and powered a 12% jump in exports year over year in the first quarter of 2026.

From Barron's • May 14, 2026

Hydro-electric plant at Electron, on the Puyallup River, producing 28,000 h. p.

From The Mountain that was 'God' Being a Little Book About the Great Peak Which the Indians Named 'Tacoma' but Which is Officially Called 'Rainier' by Williams, John H. (John Harvey)

Related Words

• heat
• service