plastid, plastid1um

[Gr. plast is (gen it. plastidos)=a female molder.] Biol.: (See extract.) which "By the recent progre of the cell theory, it has become nece ary to give the elementary organisms are usually designated as cells, the more general and more suitable name of form-units or plastids ."- Haeckel : Hist. Creation (Eng. ed.), i. 347.