noun, noun or participle which takes 'suru'
asleep; dreaming
Rare literary word for the state of being asleep or dreaming. In modern Japanese, 眠っている or 夢を見ている are used instead. Found mostly in classical or poetic contexts.
彼は夢寐の間にその言葉を口にした。
He uttered those words while asleep.
夢寐にも忘れ
It was a scene I could not forget even in my dreams.