xeno

Xeno is a productive prefix derived from the Greek xenos meaning “stranger” or “guest.” In English, it forms terms that denote foreign origin or cross-species relationships, such as xenophobia, xenograft, xenobiotics, xenolith, and xenogamy.

Xenograft and xenotransplantation describe tissue or organ transfers between species; xenobiotics are substances foreign to an organism; xenolith is a fragment of rock enclosed in another rock; xenogamy is cross-pollination between different plant species.

Xeno may also refer to attitudes toward outsiders (xenophobia) or interest in foreign cultures (xenophilia). In science fiction and popular culture, xenology and related terms describe the study or portrayal of extraterrestrial life; however, scientific study of life beyond Earth is generally called astrobiology or exobiology, not xenology.

Xeno also appears in the naming of the chemical element xenon, whose name derives from Greek xenos meaning foreign or strange, reflecting its status as a newly discovered, elusive gas at the time of its isolation.