expression, noun
dream within a dream; pie in the sky; unrealizable dream
A set phrase meaning something so unlikely it is like a dream inside another dream; used for hopes or plans that are almost impossible to realize.
宝くじで一億円当てるなんて、夢のまた夢だ。
Winning a hundred million yen in the lottery is just a dream within a dream.
世界平和は夢のまた夢かもしれないが、諦めてはいけない。
World peace may be a pie in the sky, but we must not give up.
夢物語 is a 'dream story' or 'fantasy tale', often used for unrealistic plans or narratives, while 夢のまた夢 emphasizes the extreme unlikelihood of a wish coming true.
絵空事 is a 'fabrication' or 'pipe dream', focusing on something made up or unrealistic, whereas 夢のまた夢 is a more poetic expression for an unattainable dream.
Literally 'a dream of a dream', from 夢 (dream) + の (possessive particle) + また (again, further) + 夢 (dream). The phrase suggests a dream nested within another dream, emphasizing extreme remoteness from reality.