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.

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

/bakˈtɪərɪəm/