from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of, relating to, using, producing, or caused by heat.
- adj. Intended or designed in such a way as to help retain body heat: thermal underwear.
- n. A rising current of warm air.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A column of rising air in the lower atmosphere created by uneven heating of Earth's surface.
- adj. pertaining to heat or temperature.
- adj. providing efficient insulation so as to keep the body warm.
from the GNU version of the Collaborative International Dictionary of English
- adj. Of or pertaining to heat; warm; hot.
- adj. caused by or affected by heat.
- adj. designed to retain heat.
from The Century Dictionary and Cyclopedia
- Of or pertaining to heat.
- Of or pertaining to thermæ.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. caused by or designed to retain heat
- adj. relating to or associated with heat
- n. rising current of warm air
- adj. of or relating to a hot spring
From New Latin *thermalis, from Ancient Greek θέρμη (thermē, "heat"). (Wiktionary)