'revelational' originates from Latin, specifically the Late Latin word 'revelatio' (from the verb 'revelare'), where the prefix 're-' meant 'again' or intensifying and 'velare' meant 'to veil/cover' (so 'revelare' carried the sense 'to un-veil' or 'to disclose').

'revelational' developed from the noun 'revelation' (Middle English 'revelacioun' < Old French 'revelacion' < Late Latin 'revelatio' < Latin 'revelare'), and the English adjectival form 'revelational' arose by adding the adjective-forming suffix '-al' to 'revelation'.

Initially the related Latin root concerned the action 'to un-veil' or 'make visible'; over time it evolved into meanings centered on 'disclosure of truth' or 'divine disclosure,' and now the adjective 'revelational' describes something pertaining to or causing such disclosure.