Definition of paramecium in US English:



  • A single-celled freshwater animal that has a characteristic slipper-like shape and is covered with cilia.

    Genus Paramecium, phylum Ciliophora, kingdom Protista

    • ‘Contact with protozoa, the tremendously varied group of more sophisticated single-celled microbes that includes amoeba and paramecium, has also been greatly reduced in the developed world by water and food treatment measures.’
    • ‘In 1911, he reported on the effect of hematoporphyrin and light on a paramecium and red blood cells and described skin reactions in mice exposed to light after hematoporphyrin administration.’
    • ‘Parameciums have a permanent feeding mechanism, consisting of a funnel-shaped gullet into which food is drawn by the combined action of the cilia. They feed on small organisms such as bacteria and even other smaller protozoa.’


Mid 18th century: modern Latin, from Greek paramēkēs ‘oval’ from para- ‘against’ + mēkos ‘length’.