hypothermia

Etymology

It is borrowed from New Latin hypothermia,^[2][3][4] formed from the prefix hypo- (under, below) with Ancient Greek θέρμη (thérmē, “heat”) and the noun suffix -ia.^{[5][4][6][7][8]} The Greek noun is from Proto-Indo-European *gʷʰer- (“to heat, warm”).^[4][7]

Earliest recorded meaning

A body temperature well below normal, whether natural or artificially induced: 1886, in the New Sydenham Society Lexicon.^[5] Merriam-Webster's Collegiate and Merriam-Webster Unabridged date it to about 1886,^[9][2] Etymonline to 1877,^[4] and Dictionary.com to 1885–90.^[10]

Semantic evolution

The word has kept its single medical meaning, but dictionaries weigh its two uses differently: Merriam-Webster Unabridged defines it as a low body temperature often induced on purpose to make heart surgery easier,^[2] while Collins puts first the natural condition, as in elderly people exposed to cold weather, and gives the deliberate cooling of a patient in heart and brain surgery as a second sense.^[11] The OED covers both in one definition.^[5]

Timeline

• 1886 – a body temperature well below normal, natural or induced.^[5][9][2] Etymonline dates the word to 1877.^[4]

Meanings

Noun

1. An abnormally low body temperature, especially from exposure to cold: The stranded hikers were treated for hypothermia.^{[11][7][2][5]}
2. (medicine) The deliberate lowering of a patient's body temperature to slow the metabolism, as in heart or brain surgery.^[11][2][5]

Word family

• hypothermic

Related words

• hyperthermia
• thermal
• thermometer
• hypo-

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
3. ^ Gove, Philip Babcock, ed. (1961), Webster's Third New International Dictionary of the English Language, Unabridged, Springfield, Mass.: G. & C. Merriam
4. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c d e f Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
8. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
9. ^ a b Merriam-Webster's Collegiate Dictionary (2003), 11th ed., Springfield, Mass.: Merriam-Webster
10. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
11. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins