Pro"to*plast (?), n. [L. protoplastus the first man, Gr. formed or created first; first + formed, fr. to form.]
The thing first formed; that of which there are subsequent copies or reproductions; the original.
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.
<-- 3. a plant or bacterial cell which has lost its cell wall. As a consequence, protoplasts typically assume a spherical shape, and are unable to resist rupture in a liquid of low osmolarity; but they may live and in some cases divide, provided that the osmotic pressure of the medium is sufficient to prevent expansion to the point of rupture. -->
© Webster 1913.