Where does “সরোজ” come from?

সরোজ (Bengali) comes from Sanskrit सरोज, from Sanskrit सरस्, from Proto-Indo-Aryan sáras, from Proto-Indo-Iranian sáras, from Proto-Indo-European sélos — marsh.

Ancestry of “সরোজ”, step by step

Step	Language	Word	Meaning
1	Sanskrit	सरोज	produced or found in lakes and ponds; a lotus; a...
2	Sanskrit	सरस्	pond, lake; pool, tank, pail of water; a large...
3	Proto-Indo-Aryan	sáras	—
4	Proto-Indo-Iranian	sáras	marsh, water
5	Proto-Indo-European	sélos	marsh

Every word from Proto-Indo-European sélos →Every word from Proto-Indo-Iranian sáras →Every word from Proto-Indo-Aryan sáras →