The Wikipedia (not necessarily authoritative) says:

Quote:
The Greek word xenos means "stranger" or "alien" (in the sense of "foreigner")", the common name of the xenomorph (not to be confused with the name of unknown extraterrestrial life) and morphĂȘ means "form", a Greek term that should not be confused with the English "morph". In other words, the word xenomorph itself means little more than "alien form"