An Etymological Dictionary of the German Language/Seneschall
Seneschall, m., ‘seneschal, high steward,’ from the equiv. MidHG. seneschalt, sineschalt, m., which is derived from Rom.; comp. the cognates Fr. sénéchal, Ital. siniscalco (MidLat. siniscalcus), ‘high steward.’ The Rom. words are based on an OTeut. word (Goth. *sinaskalks, ‘head servant’); comp. Goth. sinista, ‘eldest,’ which is primit. allied to OIr. sen, Lat. senex, senior, Lith. sénas, Sans. sánas, ‘old.’ With regard to the second part of the compound comp. Schalk (and Marschall). The invariable t at the end of the MidHG. word is remarkable.