Where does “盥” come from?

盥 (Japanese) comes from Japanese 手洗い, from Japanese 手, from Middle Chinese 手.

盥 (Japanese): tub, basin

Definitions

Step	Language	Word	Meaning
1	Japanese	手洗い	hand washing, washing one's hands; washing by...
2	Japanese	手	a hand; a handle, grip; a paw, foreleg
3	Middle Chinese	手	—

盥 — Etymology, Origin & Word History | Etymology Explorer