Where does “ইত্যাদি” come from?

ইত্যাদি (Bengali) comes from Sanskrit इत्यादि, from Sanskrit आदि, from Hindi आदा, from Prakrit *𑀆𑀤𑁆𑀤𑀅, from Sanskrit आर्द्रक, from Sanskrit आर्द्र.

Ancestry of “ইত্যাদি”, step by step

Step	Language	Word	Meaning
1	Sanskrit	इत्यादि	—
2	Sanskrit	आदि	beginning; commencement
3	Hindi	आदा	ginger
4	Prakrit	*𑀆𑀤𑁆𑀤𑀅	—
5	Sanskrit	आर्द्रक	wet, moist; ginger
6	Sanskrit	आर्द्र	—