a fanciful or impractical notion or hope; daydream.
- Also called air castle, castle in Spain .
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use castle in the air in a sentence
Often while the lamp burnt low, and a horse-bell jangled sadly, they laughed together in a castle-in-the-air.To Tell You the Truth | Leonard Merrick
British Dictionary definitions for castle in the air
a hope or desire unlikely to be realized; daydream
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012