thermal
adjective
[ ˈθəːm(ə)l ]
• relating to heat.
• "thermal conductivity"
thermal
noun
• an upward current of warm air, used by gliders, balloonists, and birds to gain height.
• a thermal garment, especially underwear.
Origin:
mid 18th century (in the sense ‘relating to hot springs’): from French, from Greek thermē ‘heat’.
