This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
檥 combines 木 (tree/wood) with 義, which likely contributes the sound. The exact historical development is uncertain, and the character is rare in modern Japanese.
Since the meaning is unclear, focus on the shape: a tree 木 beside 義. Picture a wooden signpost with the character 義 carved into it, marking a boundary.
For ギ, imagine a wooden gear (ギア) with 義 etched on its side: gear -> ギ, and the tree 木 provides the wood.
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