This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
楱 combines 木 (tree/wood) with 奏, which likely contributes the sound. The exact historical development is uncertain.
A tree 木 beside 奏, but the meaning is unclear. Imagine a rare wooden instrument that plays a tune (奏), but its purpose is forgotten.
For ソウ, picture a soulful tune (ソウ) coming from the wooden instrument: soul -> ソウ, and the tree 木 resonates with the sound.
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