Where does “σάββατον” come from?

σάββατον (Koine Greek) comes from Hebrew שבת, from Akkadian šapattum — 15.

Ancestry of “σάββατον”, step by step

Step	Language	Word	Meaning
1	Hebrew	שבת	Shabbat, Sabbath; weekly day of rest; Saturday;...
2	Akkadian	šapattum	15