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."
Entries linking to hypo-
*upo
Proto-Indo-European root meaning "under," also "up from under," hence "over."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit upa "near, under, up to, on," Greek hypo "under," Latin sub "under, below," Gothic iup, Old Norse, Old English upp "up, upward," Hittite up-zi "rises."
hypo-allergenic adj.
also hypoallergenic, 1950; see hypo- + allergen + -ic.