Refers to open space or the air above the ground, especially in set expressions involving something floating, hanging, or moving through the air. For outer space specifically, 宇宙 is more explicit.
from memory; by heart
Used mainly in the fixed adverbial pattern 宙で, meaning to say or do something from memory without looking at notes. The synonymous そらで is also common.
See also: 空 (そら)
The balloon is floating in the air.
The hat flew through the air in the strong wind.
The children became able to recite the multiplication table from memory.
He practiced his speech so much he could say it entirely from memory.
The ball flew so high it seemed to vanish into thin air.
As he fell, his hand grasped at empty air.
暗記 is the act of memorizing something, while 宙で describes performing or reciting it from memory after it has already been memorized.
universe; cosmos; space
somersault; looping-the-loop
hanging in midair; suspended · aerial stunt; midair stunt
dangling; hanging; suspended · pending; in limbo; indecisive; half done
aerial cartwheel; side aerial; no-handed cartwheel
sector of space; space sector
space flight; space travel
backflip; backward somersault
macrocosm; the universe; the cosmos
Standard kanji form for the reading ちゅう; common especially in expressions such as 宙に浮く and 宙を舞う.
A Sino-Japanese noun using the kanji 宙, conventionally associated with sky, space, and midair. The development of the 'by heart' sense is not certain here, but it parallels the related expression そらで.
cosmic tree; world tree
space research; space science research
midair stunt; aerial stunt
deep space
space debris; space junk