An Etymological Dictionary of the German Language/Samstag
Samstag, m., ‘Saturday,’ prop. a UpG. and Rhen. word (in MidG. and LG. Sonnabend), from MidHG. samȥtac, sampstac, OHG. sambaȥtac. In Du. zaterday, LG. sâterdach, AS. sœternesdœg, E. Saturday, which, like the equiv. OIr. dia sathairnn and Alban. šëtúne, are based on Lat. Saturni dies, unknown to Rom.; in OIc. laugardagr, þváttdagr (lit. ‘bathing day’). From the ecclesias. Lat. sabbati dies (whence Fr. samedi, Ital. sabbato, Prov. dissapte, and Ir. sapait), OHG. sambaȥ-tac, ModHG. Samstag cannot be derived, for such a derivation does not explain the HG. nasal; nor can the t of an ecclesias. Lat. word be changed to ȥ. Since OSlov. sąbota, Magy. szombat, and Rouman. sămbătă are the most closely allied to OHG. sambaȥ-, we may perhaps assume that it is of Eastern origin, which supposition is supported by the fact that Bav. pfinz-tac, ‘Thursday,’ is borrowed from Gr. πέμπτη (see Pfinztag). Although Gr. *σαμβατον, a parallel form of σάββατον, has not yet been discovered, we may infer its existence from Pers. šamba almost with certainty; the corresponding Arab., Ethiop., and Abyss. words have also a medial mb. It is manifest that an Oriental term, sambato, of the 5th cent. was introduced into UpG. and Slav. through Gr. (along with Arianism, see Kirche and Pfaffe); yet it is strange that Ulfilas uses sabbatô dags without any nasal (comp. Goth. aíkklêsjô with West-Teut. kirika, from κυριακόν).