The unit of electric charge is a measure of the amount of electric charge in a given system. The two crossword solutions for this term are Coulomb (7 letters) and Abcoulomb (9 letters). The Coulomb is the SI derived unit of electric charge, named after French physicist Charles-Augustin de Coulomb. It is defined as the amount of electric charge transported by a constant current of one ampere in one second. The abcoulomb is an obsolete unit of electric charge, equal to 10 coulombs.