What is "xeno-"

before vowels, xen-, word-forming element meaning "strange, foreign; stranger, foreigner," from Greek xeno-, comb. form of xenos "a guest, stranger, foreigner, refugee, guest-friend, one entitled to hospitality," cognate with Latin hostis (see guest (n.)). "The term was politely used of any one whose name was unknown" [Liddell & Scott].

pre. 1 Having to do with foreigners, as in xenophilia, or more commonly, xenophobia. 2 From a foreign place, as in xenolith