雼
1. Anciently the same as "宕", meaning cave or cavern.
2. (Noun) Cave; cavern, synonymous with "宕" and "过". Also refers to a cave dwelling. Etymologically, it is derived from the character formed with the "宀" (roof) component, and "碭" is a simplified phonetic element. — "Shuowen Jiezi". Note: Since the character has the "宀" component, the meaning of cave dwelling is considered the original meaning. Cave dwelling refers to an area that is open and without obstruction.
3. Extended meanings include vast or dim spaces. For example: "宕冥" (boundless and vast sky; dull and dim).