The abohm is the basic unit of electrical resistance in the emu-cgs (centimeter-gram-second) system of units (emu stands for "electromagnetic units"). One abohm is equal to 10 ohms in the SI system of units; one abohm is a nanoohm.

The emu-cgs (or "electromagnetic cgs") units are one of several systems of electromagnetic units within the centimetre gram second system of units; others include esu-cgs, Gaussian units, and Lorentz–Heaviside units. In these other systems, the abohm is not one of the units.