An Etymological Dictionary of the German Language/sitzen
sitzen, vb., ‘to sit, fit, suit,’ from the equiv. MidHG. sitzen, OHG. sizzen (from *sizzean, earlier *sittian); a primit. Teut. and also common Aryan str. vb. from the Aryan root sē̆d, Teut. sē̆t. Comp. Goth. sitan, AS. sittan, E. to sit, Du. zitten, OSax. sittian, ‘to sit, be seated.’ It corresponds to Sans. sad, Gr. ἔζομαι (for *σεδjο-), Lat. sêdeo, OSlov. sędą (sěsti). For the corresponding causative see setzen. It is unnecessary to adduce further derivatives from this very large Aryan class (such as Lat. sîdo, Gr. ἱδρύω, Lat. sella, &c.).