Pro"to*plast (?), n. [L. protoplastus the first man, Gr. &?; formed or created first; &?; first + &?; formed, fr. &?; to form.]

1. The thing first formed; that of which there are subsequent copies or reproductions; the original.

2. (Biol.) A first-formed organized body; the first individual, or pair of individuals, of a species.

A species is a class of individuals, each of which is hypothetically considered to be the descendant of the same protoplast, or of the same pair of protoplasts.