bacterium

play
noun bac·te·ri·um \ bak-ˈtir-ē-əm \

Definition of bacterium

plural bacteria play \-ē-ə\
biology :any of a domain (Bacteria) (see domain 8) of chiefly round, spiral, or rod-shaped single-celled prokaryotic microorganisms that typically live in soil, water, organic matter, or the bodies of plants and animals, that make their own food especially from sunlight or are saprophytic or parasitic, are often motile by means of flagella, reproduce especially by binary fission, and include many important pathogens; broadly :prokaryote
Note: Bacteria lack a nuclear membrane or membrane-bound organelles and are categorized as gram-positive or gram-negative when a cell wall is present. While many bacteria are aerobic requiring the presence of oxygen to survive, others are anaerobic and are able to survive only in the absence of oxygen.
— compare archaea, eukaryote

Recent Examples of bacterium from the Web

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Origin and Etymology of bacterium

New Latin, from Greek baktērion staff

Other Microbiology Terms


BACTERIUM Defined for English Language Learners

bacterium

play
noun

Definition of bacterium for English Language Learners

  • : any one of a group of very small living things that often cause disease


BACTERIUM Defined for Kids

bacterium

play
noun bac·te·ri·um \ bak-ˈtir-ē-əm \

Definition of bacterium for Students

plural bacteria \-ē-ə\
:any of a group of single-celled microscopic organisms that are important to humans because of their chemical activities and as causes of disease

Medical Dictionary

bacterium

play
noun bac·te·ri·um \ bak-ˈtir-ē-əm \

medical Definition of bacterium

plural -ria play \-ē-ə\
:any of a domain (Bacteria) of prokaryotic round, spiral, or rod-shaped single-celled microorganisms that may lack cell walls or are gram-positive or gram-negative if they have cell walls, that are often aggregated into colonies or motile by means of flagella, that typically live in soil, water, organic matter, or the bodies of plants and animals, that are usually autotrophic, saprophytic, or parasitic in nutrition, and that are noted for their biochemical effects and pathogenicity; broadly :prokaryote


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