|an extraordinary or unusual thing, person, or event; an exceptional example or instance.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|—pl n , sing -rium|
|See also prokaryote a very large group of microorganisms comprising one of the three domains of living organisms. They are prokaryotic, unicellular, and either free-living in soil or water or parasites of plants or animals|
|[C19: plural of New Latin bacterium, from Greek baktērion, literally: a little stick, from baktron rod, staff]|
bacteria bac·te·ri·a (bāk-tǐr'ē-ə)
Plural of bacterium.
bacterium bac·te·ri·um (bāk-tēr'ē-əm)
n. pl. bac·te·ri·a (-tēr'ē-ə)
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, the latter causing disease in plants or animals.
|bacterium (bāk-tîr'ē-əm) Pronunciation Key
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 Earth's 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 archaeon, prokaryote.
Our Living Language : 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.