köken: From Proto-Indo-Aryan *abʰudʰnás, from Proto-Indo-Iranian *abʰudʰnás, from Proto-Indo-European *n̥-bʰudʰnós (“bottomless”), composed of *n̥- (“privative prefix”) + *bʰudʰno- (“bottom”), from *bʰudʰmḗn; see there for more. For a similar formation compare Russian без-дна (bez-dna), Ancient Greek ἄ-βυσσος (á-bussos), English bottom-less. By surface analysis, अ- (a-) + बु॒ध्न (budhná).
Etymology tree Latin sineder. Esperanto sen Esperanto sen- Esperanto fundo Esperanto -a Esperanto senfunda From sen- (“without, -less”) + fundo (“bottom”) + -a (adjectival ending).