fur, hair, down, camel hair
毧 centers on soft animal hair: fur, down, or specifically camel hair. The meanings all point to fine, insulating body hair used for warmth or material.
毧 combines 毛 (hair) with 戎, which likely contributes the sound. The character is used for soft animal hair, especially camel hair.
The outer 毛 means hair. Inside, 戎 looks like a warrior with a spear, but here imagine a soft camel covered in thick fur: 毛 wraps around the animal, giving 毧 the meaning of fur or down.
For ジュウ, picture a soft fur coat that you wear for a long time: 'jew' (as in 'jewel') sounds close to ジュウ, and the coat is a prized possession. Imagine a jewel-like fur coat: jewel -> ジュウ.
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