- any organism too small to be viewed by the unaided eye, as bacteria, protozoa, and some fungi and algae.
Origin of microorganism
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for micro-organic
You see, the micro-organic world remained a mystery to the end.
“Pure prehuman and micro-organic chemistry,” Aaron broke in.The Little Lady of the Big House
The micro-organic world was an invisible world, a world we could not see, and we knew very little about it.
- any organism, such as a bacterium, protozoan, or virus, of microscopic size
- An organism of microscopic or submicroscopic size, especially a bacterium or protozoan.
- An organism that can be seen only with the aid of a microscope and that typically consists of only a single cell. Microorganisms include bacteria, protozoans, and certain algae and fungi. See Note at germ.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.