pronoun, locative singular feminine + emphatic particle
Analysis. imissā (locative singular feminine of ima 'this') + eva (emphatic particle 'just, precisely, exactly'), emphasizing location or circumstance: 'precisely in this'.
Etymology. ima is the proximal demonstrative pronoun (pointing to what is near the speaker), from Indo-European *i-mo- (related to Latin is, English this via different stems); eva is an emphatic particle meaning 'just' or 'only', cognate with Sanskrit eva and ultimately from the root *h₂ewǵ- (to turn, whence also 'own' and 'very').
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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