I. ˈthər-məl adjective
Etymology: Greek thermē
Date: 1756
1.
[Latin thermae public baths, from Greek thermai, plural of thermē ]
: of, relating to, or marked by the presence of hot springs
thermal waters
2.
a. : of, relating to, or caused by heat
thermal stress
thermal insulation
b. : being or involving a state of matter dependent upon temperature
thermal conductivity
thermal agitation of molecular structure
c. : having low energies of the order of those due to thermal agitation
thermal neutrons
3. : designed (as with insulating air spaces) to prevent the dissipation of body heat
thermal underwear
• ther·mal·ly -mə-lē adverb
II. noun
Date: 1933
: a rising body of warm air