word-forming element meaning "under, beneath; less, less than" (in chemistry, indicating a lesser oxidation), from Greekhypo(prep. and adverb) "under, beneath; up from under; toward and under (i.e. into)," from PIE root*upo"under." ...
before vowels,xen-, word-forming element meaning "strange, foreign; stranger, foreigner," from Greekxenos"a guest, stranger, foreigner, refugee, guest-friend, one entitled to hospitality," cognate with Latinhostis, from PIE root*ghos-ti-"stranger, guest, host." "The term was politely used ...