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Related to thermal: Thermal conductivity, Thermal decomposition, Thermal diffusivity, Thermal expansion, Thermal mass, Thermal store
1. of, relating to, caused by, or generating heat or increased temperature
2. (of garments or fabrics) specially designed so as to have exceptional heat-retaining properties
3. Meteorol a column of rising air caused by local unequal heating of the land surface, and used by gliders and birds to gain height
A relatively small-scale, rising current of air produced when the atmosphere is heated enough locally by the earth's surface to produce absolute instability in its lower layers.
Of or concerning heat.
A column of rising air heated by the sun or other phenomena. Sailplane and glider pilots use it for soaring. The pilots recognize the presence of a thermal with the help of a variometer—an instrument having two tubes with red and green indicators. A red means a downward air current, and a green means an upward air current, or a thermal. See variometer.