very small bug
蟭 centers on a very small insect or bug. The meaning is narrow and concrete, referring to a tiny creature.
蟭 combines 虫 (insect) with 焦, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound for a small insect.
The insect radical 虫 beside 焦 (which can suggest scorching or tiny specks) paints a picture of a bug so small it's like a tiny scorched speck.
For ショウ, imagine a tiny bug putting on a show under a magnifying glass: show -> ショウ, and the bug is so small you need the glass to see its performance.
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