Xenos is a word built on reciprocity. In classical Greek it named both the guest and the host — two parties bound by the sacred obligation of xenia, hospitality to strangers. The New Testament preserves this remarkable two-sidedness. In Matthew 25:35-44, welcoming 'the stranger' (xenos) is the criterion by which nations are judged, and in Acts 17:21 the Athenians and resident 'foreigners' spend their time exchanging news. Spanish extranjero, French etranger, and German Fremder all capture the outsider pole, but when Paul calls Gaius 'the host' (xenos) of the whole church in Rom 16:23, the word pivots to the opposite pole — the one who receives rather than the one received. A third, purely adjectival use surfaces in Heb 13:9 ('strange teachings') and 1 Pet 4:12 ('the fiery ordeal as though some strange thing'), where xenos modifies abstract nouns to mean simply 'unfamiliar' or 'foreign to expectation.'