This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
篂 combines 竹 (bamboo) with 星 (star), but the historical origin and original meaning are uncertain. It may have been a specialized character for a bamboo object or a variant form.
The bamboo top 竹 and star bottom 星 suggest a bamboo object related to stars, but its exact meaning is unclear. Picture a bamboo tube used for stargazing.
For セイ, imagine a bamboo star-shaped charm that brings a 'say' of good luck: say -> セイ, as you whisper a wish to the star.
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