revelatory dream; vision
A dream believed to convey a divine or supernatural message; often used in religious or spiritual contexts.
He said he received a divine message in a revelatory dream.
Compound of 霊 (rei, 'spirit, divine') and 夢 (mu, 'dream'). The exact historical origin is uncertain, but the word has been used in Japanese religious and literary contexts to denote a dream carrying a sacred message.