feminine nominative/accusative (with postposition api)
Analysis. pathaviyā (instrumental feminine singular of pathavī) + api (postposition 'even, also'), literally 'even the earth' or 'the earth too'; often used in the sense 'down to the very earth' or 'earth and all'.
Etymology. pathavī is of uncertain origin; possibly connected to the Sanskrit pṛthivī (earth), but the Pali form shows divergence. The root sense remains obscure and does not securely cognate with familiar European roots. The postposition api (even, also, too) is cognate with Latin apud (at, by) through Indo-European *apo- (off, away), here used in the sense of 'reaching unto' or 'including'.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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