The basic unit of electric charge, equal to the quantity of charge transferred in one second by a steady current of one ampere, and equivalent to 6.2415 × 10¹⁸ elementary charges, where one elementary charge is the charge of a proton or the negative of the charge of an electron. A coulomb's value in the International System differs very slightly from that in the meter-kilogram-second-ampere system of units. See Table at measurement.

Of or relating to the Coulomb force.