Where does “ϫⲱⲱⲙⲉ” come from?

ϫⲱⲱⲙⲉ (Coptic) comes from Demotic ḏmꜥ, from Egyptian ḏmꜥ — sheet of papyrus for writing; roll of papyrus;...

ϫⲱⲱⲙⲉ (Coptic): scroll, book