Thermal vs Thermic

Thermal vs Thermic

Is there some notable difference of meaning or usage between these two terms ?

Which one of this two terms is the most suited as an adjective meaning "relative to temperature" ?

Note : I posted a similar question on Physics Stack Exchange, but I'd like to hear the try of linguists on that question as well. Original question on Physics SE : https://physics.stackexchange.com/questions/518990/thermal-vs-thermic/519003#519003


Thermal is much more widely used (especially in non-scientific contexts) and with a wider range of specific meanings (referring to baths, clothing, air currents, etc). "Thermic" is much rarer, only used in technical contexts (physics, physiology, etc), and even then it is often old-fashioned and replaced by newer terms.

Merriam-Webster notes that both can refer to heat or temperature, but "thermal" also has other specific meanings as in "thermal baths" (=baths with hot springs), "thermal underwear" (=insulating underwear). Cambridge online and Macmillan online don't seem to list "thermic" at all, suggesting it is much rarer; Merriam-Webster's entry is little more than a redirect to some senses of "thermal".

Thermic seems to be an older form that has fallen out of use. "Thermics" was an old name for "thermodynamics". "Thermic" is today found in various compounds: the tool known as a "thermal lance" or "thermic lance"; the instrument called a "thermic balance" or bolometer (I think "bolometer" is the more usual name today and "thermic balance" the older). "Thermic" also features in various brand names (mainly for thermal underwear) and in scientific terms like "endothermic". In some other very specific scientific contexts it appears to still be used but that's really a matter for scientists to say what is the more common usage.

My conclusion is that I don't know your precise context, and it sounds like you don't know the precise context either, but outside of specific, scientific contexts always use "thermal" and even in those context it's not always clear-cut.

  • https://www.merriam-webster.com/dictionary/thermic
  • https://www.merriam-webster.com/dictionary/thermal
  • https://en.wikipedia.org/wiki/Thermic
  • https://en.wikipedia.org/wiki/Thermal_lance
  • https://en.wikipedia.org/wiki/Bolometer