[ thur-muhl ]
/ ˈθɜr məl /
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See synonyms for: thermal / thermals on Thesaurus.com

Also thermic. of, relating to, or caused by heat or temperature: thermal capacity.
of, relating to, or of the nature of thermae: thermal waters.
designed to aid in or promote the retention of body heat: a thermal blanket.
Meteorology. a rising air current caused by heating from the underlying surface, especially such a current when not producing a cloud.
thermals. thermal underwear.
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Origin of thermal

First recorded in 1750–60; therm- + -al1


Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022


What does thermal mean?

Thermal means caused by or related to heat or temperature.

The word thermal is used in science to describe a specific kind of energy: thermal energy. Thermal energy is produced by heating up molecules and atoms until they move fast enough to collide into each other. What we experience as heat is a flow of thermal energy. Geothermal energy involves heat generated by the earth.

Outside of science, the word thermal is most often used to mean that something is related to high temperatures or something intended to retain body heat, as in Thermal gloves are insulated to keep your hands warm in the winter. 

Thermal is sometimes used in reference to thermal springs, also known as hot springs.

The plural noun thermals is sometimes used as shorthand for thermal underwear, which is designed to retain body heat.

The word thermic can be used as a synonym of thermal, typically in technical ways in fields such as science or engineering.

Example: Thermal maps show areas of higher and lower temperatures.

Where does thermal come from?

The first records of thermal come from the 1750s. It comes from therm-, a variant of thermo-, which is derived from the Greek word thermós, meaning “hot.”

In everyday life, we usually don’t use thermal, opting for simpler, more specific words when we talk about heat and temperature. For example, we use hot and cold to describe things that have a high (hot) or low (cold) amount of thermal energy or that have a high or low temperature.

Thermal is used in the names of a variety of heat-related products, such as thermal imaging cameras, which use heat sensors, or thermal blankets, which reflect your body heat to keep you warm.

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What are some other forms related to thermal?

  • thermally (adverb)
  • hyperthermal (adjective)
  • hyperthermally (adverb)
  • nonthermal (adjective)

What are some synonyms for thermal?

What are some words that share a root or word element with thermal

What are some words that often get used in discussing thermal?

How is thermal used in real life?

Thermal is typically used in a scientific context.



Try using thermal!

Is thermal used correctly in the following sentence?

Astronauts collected information about the temperature around Earth and reported the thermal measurements back to ground control.

How to use thermal in a sentence

British Dictionary definitions for thermal

/ (ˈθɜːməl) /

Also: thermic (ˈθɜːmɪk) of, relating to, caused by, or generating heat or increased temperature
hot or warmthermal baths; thermal spring
(of garments or fabrics) specially designed so as to have exceptional heat-retaining properties
meteorol a column of rising air caused by local unequal heating of the land surface, and used by gliders and birds to gain height
(plural) thermal garments, esp underclothes

Derived forms of thermal

thermally, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for thermal

[ thûrməl ]

Of, relating to, using, producing, or caused by heat.
Intended or designed in such a way as to help retain body heat.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Scientific definitions for thermal

[ thûrməl ]

Relating to heat.
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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.