An organism that can be seen only through a microscope. Microorganisms include bacteria, protozoa, algae, and fungi. Although viruses are not considered living organisms, they are sometimes classified as microorganisms.
MICROORGANISM
Meaning of MICROORGANISM in English
NCI English Dictionary of Cancer Terms. Английский словарь раковых терминов NCI(Национальный институт злокачественных новообразований). 2012