ind (sandhi: tatra + api)
Analysis. tatra (locative adverb, 'there, in that case') + api (enclitic particle, 'even, also'); the sandhi assimilates tatra + api to tatrāpi. api adds concessive force to the locative reference: 'even in that circumstance.'
Etymology. tatra is the locative form of tat (that), from PIE *tod- (that, there), cognate with Latin iste, Greek to, English that; api is an enclitic from PIE *api (off, away), akin to Latin ab, Greek apo, English off — here used as a concessive particle meaning 'even' or 'also', retaining the sense of 'in addition to' what one might expect.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
Lite mode — plain HTML for e-readers and old browsers. Full version