Where does “Alger” come from?

Alger (French) comes from Algerian Arabic الدزَاير, from Arabic اَلْجَزَائِر, from Arabic جَزِيرَة — island.

Alger (French): Algiers

Definitions

Step	Language	Word	Meaning
1	Algerian Arabic	الدزَاير	—
2	Arabic	اَلْجَزَائِر	the islands; Algiers
3	Arabic	جَزِيرَة	island

Alger — Etymology, Origin & Word History | Etymology Explorer