conductivity, γ,σ

https://dx.doi.org/10.1351/goldbook.C01245
Reciprocal of resistivity. This quantity is a tensor in an anisotropic medium. It was formerly called specific conductance.
Source:
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 967