ind.
Etymology. A conditional particle of unknown ultimate origin. The initial y- and final -i suggest an old demonstrative stem (yad- 'that which', related to Sanskrit tad 'that') with an adverbial suffix -i; compare yathā 'as, in the manner that' (yad- + -tha). The sense shifted from 'in that case' or 'in what case' to the standard conditional.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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