xeno-, xen-, -xenic, -xenism, -xenist, -xenous, -xeny
(Greek: foreign, foreigner; alien; different; extraneous; strange, stranger; and by extension, guest)
The "x" in xeno- is pronounced "z"; "zeno". Greeks are said to have considered any stranger a "guest" and modern Greek includes xenodocheion a "guest house" or "house for guests" or its modern version of "hotel".
The etymological meaning usually denotes some aspect of a relationship involving guests or visitors of some kind.
2. The knowledge of a language which supposedly has never geen studied by certain people.
An example would be a someone who speaks French fluently and like a native, but who has never studied French, never been to a French-speaking country, nor associated with French-speakers; would be considered to be an example of xenoglossy.
2. A strange organism not usually parasitic on the host but that becomes so because of a weakened condition of the host.