unicellular

Having or consisting of one cell; one-celled.

Consisting of a single cell, as some infusorians and some cryptogams; pertaining to or exhibiting only a single cell, as most of the protozoan animals and protophytic plants, and the undeveloped ova of all metazoan animals.

Having, or consisting of, but a single cell.

Describing any microorganism that has a single cell

A single-celled organism; a unicell.

having or consisting of a single cell