Main Entry: elec·tron

Pronunciation: \i-ˈlek-ˌträn\

Function: noun

Etymology: electr- + ²-on

Date: 1891

: an elementary particle consisting of a charge of negative electricity equal to about 1.602 × 10⁻¹⁹ coulomb and having a mass when at rest of about 9.109 × 10⁻³¹ kilogram or about ¹⁄₁₈₃₆ that of a proton