Where does “Aadi” come from?

Aadi (English) comes from Tamil ஆடி, from Sanskrit आषाढ, from Sanskrit अषाढ, from Proto-Indo-Aryan *asaẓḍʰas.

Ancestry of “Aadi”, step by step

StepLanguageWordMeaning
1TamilஆடிAadi, the fourth month of the Tamil year, occurring in July-August in the Gregorian calendar. Preceded by ஆனி and followed by ஆவணி
2Sanskritआषाढthe fourth month of the Hindu lunar calendar (in which the full moon is near the constellation अषाढा)
3Sanskritअषाढinvincible, unconquerable
4Proto-Indo-Aryan*asaẓḍʰas
Every word from Proto-Indo-Aryan *asaẓḍʰasEvery word from Sanskrit अषाढEvery word from Sanskrit आषाढ