Thermal

Thermal

ther·mal
[thur-muhl] 
 
–adjective
1. Also, thermic. of, pertaining to, or caused by heat or temperature: thermal capacity.
2. of, pertaining to, or of the nature of thermae: thermal waters.
3. designed to aid in or promote the retention of body heat: a thermal blanket.

–noun
4. Meteorology . a rising air current caused by heating from the underlying surface, esp. such a current when not producing a cloud.