pronoun, genitive plural + api (even, also)
Analysis. tesaṃ (genitive plural of ta, 'of those') + api ('even, also'), typically used for emphasis or inclusion: 'of them too', 'even their'.
Etymology. ta is the demonstrative pronoun from PIE *to- (that, the), cognate with English 'that', Latin 'istud', Greek 'to'. The suffix api is an enclitic particle meaning 'also' or 'even', from PIE *ap(i)-, related to Sanskrit api.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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