Where does “سجود” come from?

سجود (Classical Persian) comes from Arabic سَجَدَ, from Arabic ج — Abbreviation of جَمْع.

Ancestry of “سجود”, step by step

Step	Language	Word	Meaning
1	Arabic	سَجَدَ	to bow down; to bow in reverence; to prostrate,...
2	Arabic	ج	Abbreviation of جَمْع