köken: Inherited from Proto-Slavic *mirъ (“peace; world”), from Proto-Balto-Slavic *meiˀrás (“peace”), from Proto-Indo-European *mey(H)-ró-s. The dual meaning of "peace" and "world" is unique to Slavic. The pre-1918 orthography had an orthographical distinction of the two identically pronounced words to avoid confusion.
köken: Borrowed from Medieval Latin ad Deum (“to God”). Compare Aragonese, Asturian, Extremaduran, and Spanish adiós, Catalan adeu, Dutch ajuus, English, French, and Occitan adieu, German tschüss, Greek αντίο (antío), Galician adeus, Italian addio, Maltese addiju, Mirandese adius, Romanian adio, Serbo-Croatian ади̏о/adȉo, Slovene adȋjo.
hail, hello, farewell, greetings! (a formal expression of greeting)
köken: Borrowed with an unspelled /h/ from Punic [script needed] (ḥawe, “live!”, 2sg. imp.), cognate to Hebrew חוה (“Chava, the biblical Eve”), and as avō from Punic [script needed] (ḥawū, 2pl. imp.), from Semitic root ḥ-w-y (live). The form might have been contaminated by Etymology 2, especially as the latter one's long vowel also ended up short via iambic shortening; this would explain the reluctance…