mud
溏 centers on soft, wet earth: mud. The meaning is narrow and concrete, referring to muddy ground or sediment.
溏 combines the water radical 氵 with 唐, which likely provides the sound. The character is used for muddy water or mud, but the exact historical development is uncertain.
Water 氵 mixed with the shape 唐 creates a pool of thick, sticky mud. Picture a puddle where the water has turned to mud.
For トウ, imagine a toe sinking into the mud: toe -> トウ, and the mud squishes around it.
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