thermal

adjective ther·mal \ ˈthər-məl \

Definition of thermal

1 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

2 :designed (as with insulating air spaces) to prevent the dissipation of body heat

thermal underwear

[Latin thermae public baths, from Greek thermai, plural of thermē]

:of, relating to, or marked by the presence of hot springs

thermal waters

—

thermally

play \-mə-lē\ adverb

See thermal defined for English-language learners

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Recent Examples of thermal from the Web

A sulfur thermal oxidizer, which captures and burns sulfur dioxide, was damaged at the Beaumont refinery.

— dino grandoni, Washington Post, "The Energy 202: We asked Texas Republicans about Harvey and climate change. Only one answered.," 30 Aug. 2017
At the company's Beaumont petrochemical refinery, Harvey damaged a sulfur thermal oxidizer, a piece of equipment that captures and burns sulfur dioxide.

— steven mufson, chicagotribune.com, "ExxonMobil refineries damaged in Harvey, releasing hazardous pollutants," 29 Aug. 2017
Southern Research is one of several organizations nationwide with WB-57 planes flying about 50,000 feet above the clouds capturing images of the sun's corona as well as thermal imaging of Mercury while the planet is clouded by the moon.

— kelly poe, AL.com, "Hundreds come to Southern Research to watch the eclipse with scientists," 21 Aug. 2017
Remember that Intel’s Core X-series family (also called the Core i9) was announced with several key omissions: namely the clock speeds of the 12-core Core i9-7920X and above, as well as the thermal design power, or TDP.

— mark hachman, PCWorld, "Intel releases final Core i9 specs and release dates—and Threadripper is faster (sometimes)," 7 Aug. 2017
Its spa is the largest in the region at 70,000 square feet and has a one-of-a-kind thermal experience, plus an integrative medical wellness center.

— lynn hammer, star-telegram, "Girls getaway," 28 July 2017
With solar power now cheaper than coal and gas, questions have been raised about China’s gung-ho investment in traditional thermal plants.

— The Economist, "One Lifebelt, One RoadChina makes Pakistan an offer it cannot refuse," 22 July 2017
The nation’s expertise at mass production is credited with making solar panels more affordable, although companies are now reviving work on thermal technology.

— anna hirtenstein, Bloomberg.com, "Solar Plants Aim to Keep Lights on at Night," 18 July 2017
The final break was first revealed in a thermal infrared image from NASA's Aqua MODIS satellite instrument.

— danica kirka, The Christian Science Monitor, "Immense iceberg finally splits from Antarctic ice shelf," 13 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'thermal.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Did You Know?

In days gone by, much of the male population of the northern states in the cold months would wear a garment of thermal underwear covering the entire body, called a union suit. Union suits kept sodbusters, cowboys, and townsfolk alike not only warm but also itchy and a little on the smelly side (back when bathing once a week was considered the height of cleanliness). Thermal imaging is photography that captures "heat pictures"--rather than ordinary light pictures--of objects. And thermal pollution occurs when industrial water use ends up warming a river in a damaging way. Small-plane pilots use thermal as a noun for a warm updraft, often over a plowed field or desert, that lifts their wings, just as it enables hawks to soar upward without moving their wings.

Origin and Etymology of thermal

Greek thermē

NEW! Time Traveler

First Known Use: 1742

See Words from the same year

Other Physics Terms

amplitude, centrifugal, centripetal, convection, gradient, hysteresis, kinetic, lase, quantum

thermal

noun

Definition of thermal

:a rising body of warm air

See thermal defined for English-language learners

Recent Examples of thermal from the Web

Guided by computer algorithms that learned from onboard sensors, predicted air patterns and planned a route forward, these gliders could seek out thermals — columns of rising hot air — and use them to stay aloft.

— cade metz, New York Times, "Microsoft Teaches Autonomous Gliders to Make Decisions on the Fly," 16 Aug. 2017
Pope currently oversees PGE's energy supply portfolio, 15 thermal, hydro and wind generation plants, and long-term resource strategy, PGE said.

— the oregonian/oregonlive, OregonLive.com, "Portland General Electric CEO Jim Piro will retire," 28 July 2017
In comparison, solar thermal was around 15 to 18 cents per kilowatt-hour until recently.

— anna hirtenstein, Bloomberg.com, "Solar Plants Aim to Keep Lights on at Night," 18 July 2017
Both vultures, black and turkey, getting off their roosts and catching the mid-morning thermals. 4: More water.

— taylor piephoff, charlotteobserver, "18 holes of golf yield 18 observations of birds," 9 June 2017
Nvidia says the Max-Q technology will let that GTX 1060 give a GTX 1080's worth of graphics power, while keeping a lid on thermals and noise.

— melissa riofrio, PCWorld, "HP Omen laptops include a first: Nvidia Max-Q graphics technology," 6 June 2017
This technology works with any power plant that converts heat into electricity, including solar thermal and nuclear energy.

— nick stockton, WIRED, "Want Efficient Energy? Try Carbon Dioxide-Powered Turbines," 26 May 2017
Next to him is Birdwell Creative Director and '80s SoCal skateboarding legend Natas Kaupas, wearing a Birdwell T-shirt over an old thermal.

— michael b. dougherty, Esquire, "These Seriously Stylish Swim Trunks Arrived Just in Time for Summer," 17 May 2017
A pair of turkey vultures soar in the warm thermals.

— david whiting, Orange County Register, "After rains, heat, wildflowers explode in Orange County," 16 Mar. 2017

First Known Use of thermal

1933

Other Climate/Meteorology Terms

monsoon, occlusion, ozone, rime, squall, zephyr

THERMAL Defined for English Language Learners

thermal

adjective

Definition of thermal for English Language Learners

: of, relating to, or caused by heat
: designed to keep you warm by preventing heat from leaving your body
: having hot water flowing out of the ground

thermal

noun

Definition of thermal for English Language Learners

: a rising current of warm air that is produced when the sun heats an area of the ground
thermals : thermal clothing or underwear

THERMAL Defined for Kids

thermal

adjective ther·mal \ ˈthər-məl \

Definition of thermal for Students

:of, relating to, or caused by heat

thermal insulation

Medical Dictionary

thermal

adjective ther·mal \ ˈthər-məl \

medical Definition of thermal

1 :of, relating to, or caused by heat

tactile and thermal senses

2 :being or involving a state of matter dependent upon temperature

thermal agitation of molecular structure

—

thermally

play \-mə-lē\ adverb

Learn More about thermal

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thermal

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thermally

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Origin and Etymology of thermal

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thermal

Definition of thermal

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First Known Use of thermal

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THERMAL Defined for English Language Learners

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Definition of thermal for English Language Learners

thermal

Definition of thermal for English Language Learners

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thermal

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thermal

medical Definition of thermal

thermally

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