electron
n.-
1 subatomic particle (n.) B2 Upper Intermediate Technical Sciencea very small part of an atom that carries a negative electrical charge.
a subatomic particle with a negative elementary electric charge that orbits the atomic nucleus.
ExampleElectricity is created when electrons move from one atom to another through a wire.
ExampleIn a covalent bond, atoms achieve stability by sharing pairs of electrons, effectively filling their outermost shells.
UsageCountable noun; often used in the plural when discussing electrical flow or chemical bonding.
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2 magnesium alloy (n.) C2 Proficiency Archaic Technical Sciencea type of strong, light metal made from magnesium that was used in the past.
a trademarked series of magnesium alloys containing varying amounts of aluminium or zinc, historically significant in early twentieth-century engineering.
ExampleThe old airplane engine was made from a lightweight electron alloy.
ExampleThe structural integrity of the vintage airframe relied on electron components, which offered an exceptional strength-to-weight ratio for the period.
Teacher's tipThis sense is largely historical and refers to a specific brand of alloy; modern speakers almost exclusively use the word to refer to the subatomic particle.
Blend of electric + ion, coined by Anglo-Irish scientist George Stoney in 1891, changed by him multiple times from an earlier electrolion and original electrine (used as early as 1874) as the name for the electric charge associated with a univalent ion. Compare electro-, -on. The particle ("corpuscule") was discovered in 1896. The name electrion was proposed for the particle in 1906 but curtailed because Hendrik Lorentz preferred electron.