parasol, umbrella
繖 centers on a portable canopy that provides shade or shelter: a parasol or umbrella.
繖 combines 糸 (thread) with 散, which likely contributes the sound and the idea of spreading or scattering, perhaps referring to the fabric of a parasol spread open.
Thread 糸 is woven into a fabric that spreads open like 散, forming a parasol or umbrella.
For サン, picture a sunny day where you need a parasol: sun -> サン, and the thread canopy shields you.
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