|the offspring of a zebra and a donkey.|
|a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.|
|a fanciful or impossible plan or hope|
|[alluding to dreams produced by smoking an opium pipe]|
A fantastic notion or vain hope, as in I'd love to have one home in the mountains and another at the seashore, but that's just a pipe dream. Alluding to the fantasies induced by smoking an opium pipe, this term has been used more loosely since the late 1800s.