par·a·me·ci·um 
(păr′ə-mēsē-əm, -shē-əm)
(păr′ə-mēsē-əm, -shē-əm)n. pl. par·a·me·ci·a (-sē-ə, -shē-ə) or par·a·me·ci·ums
Any of various slipper-shaped freshwater ciliate protozoans of the genus Paramecium, having an oral groove for feeding.
[New Latin Paramēcium, genus name, from Greek paramēkēs, oblong in shape : para-, alongside; see PARA-1 + mēkos, length; see māk- in the Appendix of Indo-European roots.]
paramecium