1

thermal

play
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
3
[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

Recent Examples of thermal from the Web

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


2

thermal

noun

Definition of thermal

:a rising body of warm air

Recent Examples of thermal from the Web

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.

First Known Use of thermal

1933

Other Climate/Meteorology Terms



THERMAL Defined for English Language Learners

thermal

play
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

play
adjective ther·mal \ ˈthər-məl \

Definition of thermal for Students

:of, relating to, or caused by heat
  • thermal insulation

Medical Dictionary

thermal

play
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


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