Medieval Latin, from Late Latin Sclavus, from Byzantine Greek σκλάβος or Σκλάβος (Sklábos), probably from earlier Σλαβῆνος (Slabēnos), from plural Σλαβῆνοι (Slabēnoi), from Proto-Slavic *slověne (plural; the singular form Proto-Slavic *slověninŭ is derived from it).
The origin of the word σκλάβος has been disputed historically. Modern etymologists accept that it refers to Slavs (Old Slavonic словѣнинъ, словѣне), who were often enslaved during the early Middle Ages, hence the semantic correspondence, and that the originally ethnic term eventually came to have a more general social meaning at some point, possibly around the 9th or 10th century as evidenced by its appearance in German texts. An alternative hypothesis, now obsolete because unexplained phonetic irregularities have to be assumed (without any evidence for such changes to have happened, there being no variant form with upsilon attested) for it to work out, holds that the word is a derivation from the Greek verb σκυλεύω (skuleuō), meaning «to get the spoils of war», a variant form of which is σκυλάω (skuláō).
- ^ F. Kluge, Etymologisches Wörterbuch der deutschen Sprache. 2002, siehe «Sklave».