This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
瑦 combines 王 (jade) with 烏 (crow). The exact historical development is uncertain, but it likely originally referred to a type of jade or stone.
The left side 王 suggests jade or a precious stone, and the right side 烏 is a crow. Imagine a crow-shaped jade ornament, but remember the meaning is uncertain.
For オ, picture a crow (烏) holding a jade (王) ring in its beak, and it lets out a surprised 'Oh!' (オ) when it sees its reflection.