This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
祹 combines 示 (altar, spirit) with 匋, but the exact historical development and original meaning are uncertain.
The left side 示 suggests a connection to spirits or altars, but the overall meaning is unclear. Think of it as a mysterious ritual object.
For トウ, imagine a tall (トウ) altar where the mysterious 祹 is placed: tall -> トウ.