masculine nominative singular, with suffix -ssa (genitive) and quotative particle -ti
Analysis. tathāgatassa + iti: tathāgata (the Thus-Gone One) in genitive case + -ssa (genitive suffix, emphatic) + iti (quotative particle 'thus, saying'); signals a reported utterance or doctrine concerning the Tathāgata.
Etymology. tathāgata: tathā (thus, in such manner) + gata (past participle of gacchati 'goes'). The compound denotes 'the one who has gone thus'—arrived at the truth as all Buddhas have done. Tathā derives from the root of demonstratives (Sanskrit tad-, Latin is-dem 'that same'); gata cognates with Latin venio 'come' and English go (both from PIE *gʰem-). The epithet emphasizes the Buddha's entry into that singular awakened state which is the very pattern (tathā) of all Buddhahood.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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