Any of the unicellular prokaryotic microorganisms of the class Schizomycetes, which vary in terms of morphology, oxygen and nutritional requirements, and motility, and may be free-living, saprophytic, or pathogenic in plants or animals.
[New Latin bactrium, from Greek baktrion, diminutive of baktron, rod; see bak- in Indo-European roots.]
bacterium[bækˈtɪərɪəm]
n
(Life Sciences & Allied Applications / Microbiology) the singular of bacteria
bacterium(bk-tîr-m)
Pluralbacteria
Any of a large group of one-celled organisms that lack a cell nucleus, reproduce by fission or by forming spores, and in some cases cause disease. They are the most abundant lifeforms on Earth, and are found in all living things and in all of the Earths environments. Bacteria usually live off other organisms. Bacteria make up most of the kingdom of prokaryotes (Monera or Prokaryota), with one group (the archaea or archaebacteria) often classified as a separate kingdom. See also archaeonprokaryote
bacterial adjective
Usage It is important to remember that bacteria is the plural of bacterium, and that saying a bacteria is incorrect. It is correct to say The soil sample contains millions of bacteria, and Tetanus is caused by a bacterium.
k-tîr
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