Main Entry: ¹ther·mal

Pronunciation: \ˈthər-məl\

Function: adjective

Etymology: Greek thermē

Date: 1742

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