thermal

The word “thermal” means relating to heat or temperature. In plain terms, relating to heat, or something (like clothing) built to keep you warm.

“Thermal” is pronounced THUR-muhl (/ˈθɝməl/ in IPA).

Here is “thermal” used in a sentence: “The factory uses thermal energy from burning coal.”

Words with a similar meaning to “thermal” include thermal column.

Depending on how it is used, “thermal” can be an adjective and a noun.

The word “thermal” comes from French. From French thermal, ultimately from Greek therme ("heat").

“Thermal” is a fairly common word in modern English.

“Thermal” has 3 distinct senses listed in this dictionary. The most common is: relating to heat or temperature.

A thermal is a rising column of warm air. Glider and paraglider pilots circle inside thermals to gain height without engine power, and soaring birds use them in exactly the same way.

Thermals are garments designed to retain body heat — typically close-fitting base layers such as thermal underwear, tops, and leggings worn in cold weather. As an adjective, thermal describes any clothing made to hold warmth in, as in "thermal socks."

Heat is a noun naming the energy itself, while thermal is an adjective meaning "relating to heat or temperature." A power station generates heat, but we call it a thermal power station. The two are not interchangeable, because thermal cannot stand alone as the name of the energy.

Frequent pairings include thermal energy, thermal imaging, thermal conductivity, thermal underwear, and thermal springs, all built on the sense "relating to heat or temperature." In weather and aviation contexts, thermal also stands alone as a noun for a rising column of warm air.