type of tree
榠 refers to a specific type of tree. The meaning is narrow and botanical, with no common abstract extensions.
榠 combines 木 (tree) with 冥, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound naming a tree.
The tree radical 木 beside 冥 suggests a tree associated with darkness or obscurity. Picture a rare, shadowy tree deep in a forest: 榠 is that mysterious type of tree.
For ベイ, imagine a bay tree growing in a dark forest: bay -> ベイ, and the tree 榠 is a type of tree found near the bay.
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