ordinal numeral with emphatic particle api; nominative singular or accusative plural
Analysis. vīsa (ordinal numeral 'twentieth') + api (emphatic particle 'even, also'), joined by sandhi: final -a of vīsa drops before the vowel a- of api, yielding vīsaṃpi (or vīsampi as a variant spelling reflecting the enclitic nature of api).
Etymology. vīsa is an ordinal form built from the cardinal vīsati 'twenty'; the cardinal derives from an Indo-European root *dwi- 'two' (cognate with English 'twenty', German 'zwanzig', Latin 'viginti'), with the suffix -ti productive in Pali numeral formation. The ordinal -a ending marks 'the twentieth (in a sequence)'. api is a pan-Indic particle meaning 'even, also, too'; its concrete sense is of 'fitting on top of', 'adding to', hence the abstract emphatic or concessive force.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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