This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
箶 combines 竹 (bamboo) with 胡, which likely contributes the sound コ. The exact historical development is uncertain.
The top 竹 suggests bamboo, and the bottom 胡 gives the sound. Without a clear meaning, picture an ancient bamboo object whose name sounds like コ.
For コ, imagine a small bamboo cup: cup -> コ, and the bamboo 竹 on top reminds you it's made of bamboo.