adverb (with vocative particle vuso)
Analysis. addhā (adverb of certainty) + vuso (vocative particle used in addressing; from vosagga "release")
Etymology. addhā derives from Sanskrit addhā, related to the root meaning "direct, straight"; originally a locative or instrumental form carrying the sense of directness, hence certainty. The form appears to have roots in Indo-European *ad- "to, at" (Latin ad-), though the development to "certainly" is Indic.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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