Where does “प्रधान” come from?

प्रधान (Old Marathi) comes from Sanskrit प्रधान, from Sanskrit प्रधत्ते — to place before.

Ancestry of “प्रधान”, step by step

Step	Language	Word	Meaning
1	Sanskrit	प्रधान	chief, foremost, most important; pre-eminent;...
2	Sanskrit	प्रधत्ते	to place before