a fanciful or impractical notion or hope; daydream.
It was not easy to take up the old routine and forget the air castle.
Saxe Holm’s Stories Helen Hunt Jackson
All daydreaming builds this air castle; all ambition has this as its goal.
The Nervous Housewife Abraham Myerson
He passes to-day in building an air castle for to-morrow, or in writing yesterday’s elegy.
An English Grammar W. M. Baskervill and J. W. Sewell
This was enough to cause nearly every one to look upon it as a bubble or air castle.
Scientific American Supplement No. 275 Various
Bud started out next day with three different samples for the assayer, and an air castle or two to keep him company.
Cabin Fever B. M. Bower
Moreover, to teach school had long been her secret ambition, the solid foundation of many an air castle.
Rim o’ the World B. M. Bower
But, if you value your peace of mind, do not build too gorgeous an air castle on the foundation of this printed thing.
The Fiction Factory John Milton Edwards
You are not talking airship now, Stanny; it’s an air castle you have in mind.
Our Young Aeroplane Scouts in Germany Horace Porter
“I should like to be the queen of something more substantial than an air castle,” she replied laughingly.
A Fair Mystery Bertha M. Clay
The dreamer of the future will not dare to build an air castle without at least an option on the site.
Major Prophets of To-Day Edwin E. Slosson
a hope or desire unlikely to be realized; daydream
- Air cavalry
an infantry or reconnaissance unit transported by air to combat areas. Historical Examples “A V and a half of air cavalry, circling around,” Heshto said. Oomphel in the Sky Henry Beam Piper Klem Zareff called in his air cavalry to help control the sightseers. The Cosmic Computer Henry Beam Piper Here the air cavalry, the […]
- Air cavalryman
a soldier assigned to the air cavalry.
- Air cell
Anatomy, Zoology, Botany. a cavity or receptacle containing air. Electricity. a cell in which the positive electrode is depolarized by the oxygen in the air. Historical Examples I inhaled great draughts of the dry, pure air, which seemed to penetrate to my very toes, and open every air cell in my body. From North Carolina […]
- Air chamber
a chamber containing air, as in a pump, lifeboat, or organic body. Also called air cushion. a compartment of a hydraulic system containing air that by its elasticity equalizes the pressure and flow of liquid within the system. Historical Examples If the contents appear cloudy and the air chamber larger, the egg is not fresh. […]