Conductivity (k&obreve_;ndŭkt&ibreve_;v&ibreve_;t&ybreve_;), n. The quality or power of conducting, or of receiving and transmitting, as heat, electricity, etc.; as, the conductivity of a nerve.
[1913 Webster]

Thermal conductivity (Physics), the quantity of heat that passes in unit time through unit area of a plate whose thickness is unity, when its opposite faces differ in temperature by one degree. J. D. Everett. -- Thermometic conductivity (Physics), the thermal conductivity when the unit of heat employed is the heat required to raise a unit volume of the substance one degree.
[1913 Webster]