Definition of bacterium in English:

bacterium

noun

  • A member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease.

    • ‘The cholera bacterium may also live in the environment in brackish rivers and coastal waters.’
    • ‘Almost any germ, whether a bacterium or a virus, may be responsible.’
    • ‘He added that because the virus was not a bacterium, it could not be brought under control by the use of antibiotics.’
    • ‘Various germs such as fungi and bacteria live harmlessly on the skin and inside the body.’
    • ‘The membrane lipids of thermophilic bacteria are rich in saturated fatty acids.’
    • ‘A gene from a human pathogen is inserted into a bacterium that infects plants.’
    • ‘In Peru, ballast water has been blamed for the introduction of a bacterium that causes cholera.’
    • ‘Most chest infections are usually caused by germs such as bacteria or viruses.’
    • ‘The toxin produced by the diphtheria bacteria may also damage the heart and the nervous system.’
    • ‘Typhoid fever is a serious infection caused by the bacterium Salmonella typhi.’
    • ‘It is an acute, life-threatening febrile illness caused by the bacterium Salmonella typhi.’
    • ‘After the patient takes the antibiotic, it is absorbed through the cell wall of the bacterium.’
    • ‘The disease is a form of pneumonia caused by bacteria which live in water droplets.’
    • ‘The bugs are only a few thousandths of a millimetre across and lack the cell walls which most bacteria have.’
    • ‘Antibiotics cannot treat roseola because it is caused by a virus, not a bacterium.’
    • ‘The pneumococcal bacterium is the second most common cause of bacterial meningitis.’
    • ‘A urine test can also be used to confirm that the bacteria are the Legionella bacteria.’
    • ‘It could only be detected by its ability to kill bacteria on a petri dish.’
    • ‘The free radicals have the additional benefit of killing bacteria, viruses and spores.’
    • ‘Its main study area is infectious diseases caused by viruses, bacteria and parasites.’
    illness, ailment, infection, disease, disorder, sickness, affliction, malady, complaint, upset, condition, infirmity, indisposition, malaise
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Usage

Bacteria is the plural form (derived from Latin) of bacterium. Like any other plural it should be used with the plural form of the verb: the bacteria causing salmonella are killed by thorough cooking, not the bacteria causing salmonella is killed by thorough cooking. However, the unfamiliarity of the form means that bacteria is sometimes mistakenly treated as a singular form, as in the example above

Origin

Mid 19th century: modern Latin, from Greek baktērion, diminutive of baktēria ‘staff, cane’ (because the first ones to be discovered were rod-shaped). Compare with bacillus.

Pronunciation

bacterium

/ˌbakˈtirēəm//ˌbækˈtɪriəm/