An Etymological Dictionary of Astronomy and Astrophysics

The → antiparticle of the → electron, which has the same → mass, → spin, and → electric charge as the electron, but the charge is → positive. Positrons may be generated by
→ radioactive decay or by → pair production from energetic → gamma ray photons.

See also: From posi(tive), → positive + (elec)tron→ electron.