This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 宆 is uncertain. It visually combines 宀 (roof) and 弓 (bow), but the original meaning and component relationship are unclear.
With no clear meaning, picture a roof 宀 over a bow 弓 as a mysterious object stored in an attic, its purpose unknown.
For キュウ, imagine a bow 弓 under a roof 宀, and the bow's string twangs with a sharp 'kyuu' sound: キュウ.