plasm

noun3

1. •
   A mold or matrix in which anything is cast or formed to a particular shape.
2. •
   A membrane or cell layer, especially one in an embryo that later develops into a structure; the constituent cells of such a layer.
3. •
   (no longer used) Protoplasm.

   • "And that the germ plasm is different from the parthenogenetic egg?" "Why, surely!" I cried, and gloried in my own audacity. — 1912