Thermal conductivity
Thermal conductivity (k, also denoted as λ or κ) is a measure of a material's ability to conduct heat. Heat transfer across materials of high thermal conductivity occurs at a higher rate than across materials of low thermal conductivity. In the International System of Units (SI), thermal conductivity is measured in watts per meter Kelvin (W/(m•K)). In the Imperial System of Measurement (British Imperial, or Imperial units), thermal conductivity is measured in Btu/(hr•ft⋅F).