thermal

Etymology

From French thermal, from New Latin *thermalis, from Ancient Greek θέρμη (thérmē, “heat”).

Pronunciation

• IPA^(key): /ˈθɝməl/
• Rhymes: -ɜː(ɹ)məl

Noun

thermal (plural thermals)

1. (meteorology) A column of rising air in the lower atmosphere created by uneven heating of Earth's surface.

Adjective

thermal (not comparable)

1. Pertaining to heat or temperature.
   • 2013 May-June, Charles T. Ambrose, “Alzheimer’s Disease”, in American Scientist, volume 101, number 3, page 200:

     Similar studies of rats have employed four different intracranial resorbable, slow sustained release systems—surgical foam, a thermal gel depot, a microcapsule or biodegradable polymer beads.

2. (fabric) Providing efficient insulation so as to keep the body warm.
3. Caused, brought about by heat.
4. (stone) Having a rough finish by treatment with a blow-torch.

Verb

thermal (third-person singular simple present thermals, present participle thermaling or thermalling, simple past and past participle thermaled or thermalled)

1. (stone) To create a rough finish on stone by treating it with a high-temperature blow-torch.
2. (gliding, often in the present participle) To fly an unpowered aircraft in a (thermal) column of rising air.

Further reading

• thermal in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913
• thermal in The Century Dictionary, The Century Co., New York, 1911

Etymology

From Ancient Greek.

Pronunciation

• IPA^(key): /tɛʁ.mal/

Adjective

thermal (feminine singular thermale, masculine plural thermaux, feminine plural thermales)

1. thermal

Further reading

• “thermal” in le Trésor de la langue française informatisé (The Digitized Treasury of the French Language).