A measurement of a temperature difference by which an object or material resists a heat flow. Open English WordNet

In heat transfer, thermal engineering, and thermodynamics, thermal conductance and thermal resistance are fundamental concepts that describe the ability of materials or systems to conduct heat and the opposition they offer to the heat current. Wikipedia

A measure of difficulty of heat transfer through a substance Wikipedia Disambiguation

Objects' resistance to heat transfer; reciprocal of thermal conductance Wikidata