k or k-Value: Thermal conductivity; the time rate of heat flow through a unit area of a homogeneous material in a direction perpendicular to isothermal planes induced by a unit temperature gradient. It is the number of BTUs that pass through a 1-inch (25 mm) thickness of a 1 square foot (0.09 m2) sample of material in 1 hour with a temperature difference between the two surfaces of 1°F.
Kilo: Prefix meaning 1000 times the root word.
