surname
厙 is a rare kanji used primarily as a surname. Its standalone meaning is unclear beyond that name usage.
厙 combines 厂 (cliff or enclosure) with 車 (vehicle), but the exact historical development and original meaning are uncertain. It may have originally referred to a place or structure related to vehicles, but this is speculative.
The outer 厂 suggests a shelter or cliff, and inside is 車 (vehicle). Picture a family name associated with a garage or carriage house under a cliff.
For シャ, imagine a family with the surname 厙 living in a sha(ck) by the cliff: shack -> シャ, tying the sound to the shelter-like shape.
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