sandhi contraction: tad + assa
Analysis. tad (neuter nominative singular demonstrative pronoun 'that') + assa (genitive singular masculine of so 'he', or optative of atthi 'to be'). The contraction shows the elision of d before a in rapid speech.
Etymology. tad from Indo-European *tod- (that, the one), cognate with Latin tod- (in demonstratives), Greek to- (article, as in tó 'the'); assa from *es- (to be), the same root as English is, Latin esse, Greek einai.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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