Definition of microorganism Microorganism

/majˌkɹowɔˈɹgʌnɪˌzʌm/ - [maykroworgunizum] - mi•cro•or•gan•ism

We found 5 definitions of microorganism from 5 different sources.

What does microorganism mean?

WordNet

Noun Plural: microorganisms
microorganism - any organism of microscopic size
		micro-organism
		being, organism the state or fact of existing; "a point of view gradually coming into being"; "laws in existence for centuries"
		animal, animate being, beast, brute, fauna, creature a living organism characterized by voluntary movement
		plant life, flora, plant (botany) a living organism lacking the power of locomotion
		monad (biology) a single-celled microorganism (especially a flagellate protozoan)
		intestinal flora harmless microorganisms (as Escherichia coli) that inhabit the intestinal tract and are essential for its normal functioning
		virus (virology) ultramicroscopic infectious agent that replicates itself only within cells of living hosts; many are pathogenic; a piece of nucleic acid (DNA or RNA) wrapped in a thin coat of protein
		moneran, moneron organisms that typically reproduce by asexual budding or fission and whose nutritional mode is absorption or photosynthesis or chemosynthesis
		bacteria, bacterium (microbiology) single-celled or noncellular spherical or spiral or rod-shaped organisms lacking chlorophyll that reproduce by fission; important as pathogens and for biochemical properties; taxonomy is difficult; often considered to be plants
		microbe, germ, bug a minute life form (especially a disease-causing bacterium); the term is not in technical use
		pathogen any disease-producing agent (especially a virus or bacterium or other microorganism)
		protoctist any of the unicellular protists
		protist, protistan free-living or colonial organisms with diverse nutritional and reproductive modes
		pilus hairlike structure especially on the surface of a cell or microorganism
		microflora microscopic plants; bacteria are often considered to be microflora

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Wiktionary

microorganism (Noun)
An organism that is too small to be seen by the unaided eye, especially a single-celled organism, such as a bacterium.

Webster DictionaryWebster's Unabridged Dictionary 📘

microorganism (n.)
Any microscopic form of life; -- particularly applied to bacteria and similar organisms, esp. such are supposed to cause infectious diseases.

Wikipedia

A microorganism or "microbe" is a living thing (organism) that is too small to be visible to the human eye (microscopic). The study of microorganisms is called microbiology. Microorganisms can be bacteria, fungi, archaea or protists.

Viruses and prions are not called microorganisms because they are classified as non-living. Micro-organisms are often described as single-celled, or unicellular organisms, but there are unicellular protists that are visible to the human eye, and some multicellular species are microscopic.

Microorganisms live almost everywhere on earth where there is liquid water, including hot springs on the ocean floor and deep inside rocks within the earth's crust.

Microorganisms are critical to nutriend recycling in ecosystems as they act as decomposers. As some mictoorganisms can also fix nitrogen, they are an important part of the nitrogen cycle. However, pathogenic microbes can invade other organisms and therefore cause disease.