adj. & n.
--adj.
1. of, for, or producing heat.
2 promoting the retention of heat (thermal underwear).
--n. a rising current of heated air (used by gliders, balloons, and birds to gain height).
Phrases and idioms:
British thermal unit the amount of heat needed to raise
1. lb. of water at maximum density through one degree Fahrenheit, equivalent to 1.055 x 10(3) joules. thermal capacity the number of heat units needed to raise the temperature of a body by one degree. thermal neutron a neutron in thermal equilibrium with its surroundings. thermal reactor a nuclear reactor using thermal neutrons. thermal springs springs of naturally hot water. thermal unit a unit for measuring heat.
Derivatives:
thermalize v.tr. & intr. (also -ise). thermalization n. thermally adv.
Etymology: F (as THERM)