மாநாடு (Tamil) comes from Tamil மா-, from Tamil மா, from Old Tamil 𑀫𑀸, from Sanskrit महा, from Proto-Indo-Aryan maźʰā́, from Proto-Indo-Iranian maȷ́ʰā́, from Proto-Indo-European méǵh₂s — big, great.
மாநாடு (Tamil): conference, summit, meeting