The $\textit{BTU (TH) Inch per Square Foot Second Degree Fahrenheit}$ is an Imperial unit for 'Thermal Conductivity' expressed as: $$Btu_{th} \cdot in/(ft^{2} \cdot s \cdot degF)$$.
Unit of thermal conductivity according to the Imperial system of units
British Thermal Unit (thermochemical Definition) Inch per Square Foot Second Degree Fahrenheit