Pipe dream is a term used to describe an unrealistic or unattainable goal. It is often used to refer to a plan or ambition that is unlikely to be achieved. The crossword solutions for this term include HOPE (4 letters), CHIMERA (7 letters), ILLUSION (8 letters), DELUSION (8 letters), DAYDREAM (8 letters), REVERIE (7 letters), ILLUSORY (8 letters), IMAGINARY (9 letters), and pieinthesky (11 letters). All of these words are related to the concept of pipe dream, as they all refer to something that is not real or attainable.