The name "abcoulomb" was introduced by Kennelly in 1903 as a short form of (absolute) electromagnetic cgs unit of charge that was in use since the adoption of the cgs system in 1875.
[1] The abcoulomb was coherent with the cgs-emu system, in contrast to the coulomb, the practical unit of charge that had been adopted too in 1875.
In the electromagnetic cgs system, electric current is a fundamental quantity defined via Ampère's law and takes the permeability as a dimensionless quantity (relative permeability) whose value in a vacuum is unity.
As a consequence, the square of the speed of light appears explicitly in some of the equations interrelating quantities in this system.
The abcoulomb is the charge flowing in 1 second given a current of 1 abampere.