An Etymological Dictionary of Astronomy and Astrophysics

The unit of → electric charge in the → mks system,
equal to the quantity of charge transferred in one second by a steady current of one → ampere. One coulomb represents a charge of approximately 6.241 506 × 10¹⁸ → electrons. Compared with the charge unit in the → cgs system, 1 C = 2.998 × 10⁹ → esu.

See also: Named after the French physicist Charles Augustin de Coulomb (1736-1806), who pioneered research into magnetism and electricity.