thermal

[thur-muh l] /ˈθɜr məl/

adjective

Also, thermic. of, pertaining to, or caused by heat or temperature:

thermal capacity.

of, pertaining to, or of the nature of thermae:

thermal waters.

designed to aid in or promote the retention of body heat:

a thermal blanket.

noun

Meteorology. a rising air current caused by heating from the underlying surface, especially such a current when not producing a cloud.

thermals, thermal underwear.

Origin

1750-60; therm- + -al¹

Related forms

thermally, adverb

hyperthermal, adjective

hyperthermally, adverb

nonthermal, adjective

nonthermally, adverb

Examples from the web for thermal

Solar thermal systems use heat energy from the sun to warm water.
One guaranteed way to chill out these days is in a hot spring at a thermal spa.
Remarkable is the thermal gap between day and night.
Another technology that archaeologists are taking to is thermal imaging.
People typically don't think of installing solar thermal when they build or retrofit their homes.
thermal annealing of these thin-film devices often leads to improved power conversion efficiency.
Because hillsides are never as cold in winter as the hilltops above them or the ground below them, they're called thermal belts.
The hotter they are and the bigger they are, the more thermal energy they have.
thermal comfort always rated poorly compared with other categories.
All the progress your correspondent has witnessed since the early days of thermal airships leaves him wanting more.

British Dictionary definitions for thermal

thermal

/ˈθɜːməl/

adjective

Also thermic (ˈθɜːmɪk). of, relating to, caused by, or generating heat or increased temperature

hot or warm: thermal baths, thermal spring

(of garments or fabrics) specially designed so as to have exceptional heat-retaining properties

noun

(meteorol) a column of rising air caused by local unequal heating of the land surface, and used by gliders and birds to gain height

(pl) thermal garments, esp underclothes

Derived Forms

thermally, adverb

Word Origin and History for thermal

adj.

1756, "having to do with hot springs," from French thermal (Buffon), from Greek therme "heat," from PIE *ghwerm-/*ghworm- "warm" (cf. Latin fornax "an oven, kiln," formus "warm," Old English wearm; see warm). Sense of "having to do with heat" is first recorded 1837. The noun meaning "rising current of relatively warm air" is recorded from 1933.

thermal in Medicine

thermal ther·mal (thûr'məl)
adj.

Of, relating to, using, producing, or caused by heat.
Intended or designed in such a way as to help retain body heat.

thermal in Science

thermal

  (thûr'məl)
Adjective  Relating to heat.

Noun  A usually columnar mass of warm air that rises in the lower atmosphere because it is less dense than the air around it. Thermals form because the ground surface is heated unevenly by the Sun. The air usually rises until it is in equilibrium with the air surrounding it.