Where does “आदि” come from?

आदि (Hindi) comes from Sanskrit आदि, from Hindi आदा, from Prakrit *𑀆𑀤𑁆𑀤𑀅, from Sanskrit आर्द्रक, from Sanskrit आर्द्र — wet, moist, damp.

आदि (Hindi): beginning, source, origin; et cetera, and so on;...