noun
account of a dream
Literal meaning: a story or description of what happened in a dream.
朝起きて、昨夜の夢物語を家族に話した。
When I woke up, I told my family the account of last night's dream.
noun
fantastic story; pipe dream
Idiomatic use: an unrealistic, fanciful story or idea, like something out of a dream. Often used dismissively.
彼の成功談は夢物語に過ぎない。
His success story is nothing more than a pipe dream.
そんな計画は夢物語だよ。
That plan is just a fantasy.