A single-celled aquatic flagellate of the genus Euglena, which is treated as either a protozoan or an alga. Cf. euglenoid, adj. n.

A unicellular organism; an ovum. Also: any of the particles of which cellular protoplasm is supposedly composed (rare).

A multicellular organism.

An organism consisting of a number of cells all of the same kind. Opposed to heteroplastide and monoplastide.

= monoplast, n.

Biology. A diploid organism.