1877, Modern Latin, from hypo- "under" (see hypo-) + Greek therme "heat" (from PIE root *gwher- "to heat, warm") + abstract noun ending -ia.
Entries linking to hypothermia
hypo-
word-forming element meaning "under, beneath; less, less than" (in chemistry, indicating a lesser oxidation), from Greek hypo (prep. and adverb) "under, beneath; up from under; toward and under (i.e. into)," from PIE root *upo "under."
*gwher-
Proto-Indo-European root meaning "to heat, warm."
It forms all or part of: brand; brandish; brandy; brimstone; brindled; forceps; Fornax; fornicate; fornication; fornix; furnace; hypothermia; thermal; thermo-; Thermopylae; Thermos.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit gharmah "heat;" Old Persian Garmapada-, name of the fourth month, corresponding to June/July, from garma- "heat;" Hittite war- "to burn;" Armenian jerm "warm;" Greek thermos "warm;" Latin formus "warm," fornax "oven;" Old Irish fogeir "heated;" Old English bærnan "to kindle."
-ia
word-forming element in names of countries, diseases, and flowers, from Latin and Greek -ia, noun ending, in Greek especially used in forming abstract nouns (typically of feminine gender); see -a (1). The classical suffix in its usual evolution (via French -ie) comes to Modern English as -y (as in familia/family, also -logy, -graphy). Compare -cy.
In paraphernalia, Mammalia, regalia, etc. it represents Latin or Greek -a (see -a (2)), plural suffix of nouns in -ium (Latin) or -ion (Greek), with formative or euphonic -i-.