Where does “sodium” come from?

sodium (New Latin) comes from Italian soda, from Arabic سُوَّاد — saltwort.

Ancestry of “sodium”, step by step

Step	Language	Word	Meaning
1	Italian	soda	soda, sodium carbonate; soda water; third-person...
2	Arabic	سُوَّاد	saltwort

sodium — Etymology, Origin & Word History | Etymology Explorer