protoplast UK /ˈpɹəʊ.təˌplæst/US /ˈpɹoʊ.təˌplæst/noun 4adjective 1forms 3 noun4 •The contents of a plant cell. •The first-created human; Adam. •The first person in a given family, lineage etc.; an ancestor.Habsburg tradition insists that the protoplast of the family was called Guntram. — 2011 •(rare) A prototype or archetype; a model. adjective1 •(no longer used) Created first; archetypal. formsprotoplasts · more protoplast · most protoplast