Electrical conductivity is the measure of a material's ability to allow the transport of an electric charge. Its SI is the siemens per metre, (A2s3m−3kg−1) (named after Werner von Siemens) or, more simply, Sm−1.
It is the ratio of the current density to the electric field strength. It is equivalent to the electrical conductance measured between opposite faces of a 1-metre cube of the material under test.
The symbol for electrical conductivity is κ (kappa), and also ς (sigma) or γ (gamma).