1. Of or pertaining to heat; warm; hot; as, the thermal unit; thermal waters.
The thermal condition of the earth. --J. D. Forbes.
Thermal conductivity, Thermal spectrum. See under Conductivity, and Spectrum.
Thermal unit Physics, a unit chosen for the comparison or calculation of quantities of heat. The unit most commonly employed is the amount of heat necessary to raise the temperature of one gram or one pound of water from zero to one degree Centigrade. See Calorie, and under Unit.
Con·duc·tiv·i·ty n. The quality or power of conducting, or of receiving and transmitting, as heat, electricity, etc.; as, the conductivity of a nerve.
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.