n 1  cap  :  a genus of large parasitic ciliate protozoans (order Heterotricha) including one (B. coli) that infests the intestines of some mammals and esp. swine and may cause a chronic ulcerative dysentery in humans  2  pl  -ia   :  a protozoan of the genus Balantidium bal*an*tid*i*al or  bal*an*tid*ic  adj 
 
 
 
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