This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
哃 combines 口 (mouth) with 同, which likely provides the sound. The exact historical development is uncertain.
The mouth 口 beside 同 suggests a sound or utterance, but the specific meaning is unclear. Think of it as a rare character related to speech.
For トウ, imagine a toe tapping inside a mouth: toe -> トウ, and the mouth 口 makes a tapping sound.