This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
磲 combines 石 (stone) with 渠, which likely contributes the sound. The exact historical development is uncertain.
The stone radical 石 suggests a connection to rocks or minerals, but the overall meaning is unclear. Picture a mysterious stone with the shape of 渠 carved into it.
For キョ, imagine a giant stone key (キー) that fits into a stone lock: key -> キョ, and the stone is the 磲.
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