Left: thread 糹/糸 (here: fiber), right: clan/family name 氏 (Here: see 氏 as ladle or scooping grill for the paper production) [Family 氏 = A distorted person 人 = 亻= 厂 together with "Plus +" as multiplier makes a family.]
Mnemonic
Use cellulose fibers and a grill for making paper. (OR: Threads become a 'family' in: paper.)
Variant of hill 丘. Clan families often had their estates on the top of hills. This developed into the family name. It can be seen as one person 人, which is modified as: 厂 and a “plus +” as a multiplier, so that many persons form a family.
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