This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
礞 combines 石 (stone) with 蒙, which likely contributes the sound. The exact historical development is uncertain.
The left side is 石 (stone) and the right side is 蒙 (a component associated with covering or dimness). Picture a stone covered in mist, its meaning unclear.
For ボウ, imagine a bow made of stone: bow -> ボウ, but the stone bow is too heavy to use.