This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
腩 combines the flesh radical ⺼ with 南, but the exact historical development and original meaning are uncertain.
The flesh radical ⺼ suggests a body part, but the overall meaning is unclear. Think of it as a mysterious body-related kanji.
For ナン, imagine a nan bread made of flesh: nan -> ナン, though the meaning is uncertain.
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