Abmho or absiemens is a unit of electrical conductance in the centimetre gram second (emu-cgs) system of units. It's equal to gigasiemens (inverse of nano-ohm).
The emu-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 abmho is not one of the units.
References
Abmho Wikipedia(Text) CC BY-SA