Pronunciation: (i-lek'tron),[key] —n. 1. Also called negatron.Physics,Chem.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. Elect.a unit of charge equal to the charge on one electron.