The origin of the name is the subject of scholarly discussions. Hungarian linguists and historians suggested the derivation from the Hungarian
sojó, só folyó (salt water, river) already in the 19th century. Newer theories associate the name with
sió referring to fast streams. According to Slovak linguists, the name is pre-Hungarian (
Slaná: salt river) and most likely not associated with the salinity but with the
salt road existing already in times of
Great Moravia. The supporters argue by citing numerous Slavic toponyms in the river basin and by local names related to
soľ (salt) and Moravia like
Moravce,
Soľár,
Solišče,
Soľka,
Soľník,
Morava (according to this interpretation the Hungarian name is a later translation). ==References==