Where does “तीन” come from?
तीन (Hindi) comes from Old Hindi तीनि, from Sauraseni Prakrit 𑀢𑀺𑀡𑁆𑀡𑀺, from Ashokan Prakrit 𑀢𑀺𑀁𑀦𑀺, from Sanskrit त्रीणि, from Sanskrit त्रि, from Proto-Indo-Aryan tráyas, from Proto-Indo-Iranian tráyas, from Proto-Indo-European *tréyes.
तीन (Hindi): three
Ancestry of “तीन”, step by step