par·​a·​me·​cium | \ ˌper-ə-ˈmē-sh(ē-)əm How to pronounce paramecium (audio) , -sē-əm, ˌpa-rə- \
plural paramecia\ ˌper-​ə-​ˈmē-​sh(ē-​)ə How to pronounce paramecia (audio) , -​sē-​ə , ˌpa-​rə-​ \ also parameciums

Definition of paramecium

: any of a genus (Paramecium) of ciliate chiefly freshwater protozoans that have an elongate body rounded at the anterior end and an oblique funnel-shaped buccal groove bearing the mouth at the extremity

First Known Use of paramecium

1752, in the meaning defined above

History and Etymology for paramecium

borrowed from New Latin Paramecium, pre-Linnaean name for protozoa of the genus, from Greek paramḗkēs "oblong, oval" (from para- para- entry 1 + -mēkēs, adjective corresponding to mêkos "length, height, magnitude") + New Latin -ium -ium — more at meager

Note: The name Paramecium was introduced, in both Latin descriptions and English descriptions maintaining the Latin coinage Paramecium, by the English polymath John Hill (ca. 1714-1775) in An History of Animals (London, 1752, vol. 3 of his A General Natural History), p. 4. The word was first used as a Linnaean genus name by Otto Frederik Müller in Vermivm terrestrium et fluviatilium, seu, Animalium infusoriorum…succincta historia, vol. 1 (Copenhagen & Leipzig, 1773), p. 54 (spelled unetymologically Paramæcium, corrected in later publications).

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Cite this Entry

“Paramecium.” Dictionary, Merriam-Webster, Accessed 1 Dec. 2020.

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More Definitions for paramecium


par·​a·​me·​cium | \ ˌper-ə-ˈmē-shē-əm How to pronounce paramecium (audio) , -sē-əm \
plural paramecia\ -​shē-​ə , -​sē-​ə \ also parameciums

Kids Definition of paramecium

: a tiny living thing found in water that is a single cell shaped like a slipper and moves by means of cilia


par·​a·​me·​cium | \ ˌpar-ə-ˈmē-sh(ē-)əm, -sē-əm How to pronounce paramecium (audio) \

Medical Definition of paramecium

1 capitalized : a genus of ciliate protozoans that have an elongate body rounded at the anterior end and an oblique funnel-shaped buccal groove bearing the mouth at the extremity
2 plural paramecia\ -​sh(ē-​)ə, -​sē-​ə How to pronounce paramecia (audio) \ also parameciums : any ciliate protozoan of the genus Paramecium

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