neuter nominative/accusative singular in -aṁ sandhi form (gahanañhetaṁ = gahana + ñ + hetaṁ, contracted from gahanassa hetaṁ 'because of depth')
Analysis. gahana (dense, deep, thick) + ñ (genitive sandhi connector) + hetaṁ (because of, by reason of) — 'because of depth/obscurity'
Etymology. gahana from √gah (to plunge, dive) with -ana suffix; related to English 'go' and Sanskrit gāḍha 'deep'. The spatial sense of plunging downward became the abstract meaning of depth and obscurity.
Meanings from the Digital Pāḷi Dictionary; morphology and etymology by Claude.
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