This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
秱 combines 禾 (grain) with 同, which likely contributes the sound. The exact historical meaning is uncertain, and the character is rare in modern Japanese.
The left side 禾 suggests grain, and the right side 同 looks like a container. Picture grain being stored in a container, though the exact meaning is unclear.
For トウ, imagine a toe (トウ) accidentally stepping into a container of grain: toe -> トウ, and the grain spills from the 秱 container.
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