n 1  :  a small plug of sebum blocking the duct of a sebaceous gland esp. on the face - compare MILIUM   2  :  a destructive disease of turkeys and related birds caused by a protozoan of the genus Histomonas (H. meleagridis) that invades the intestinal ceca and liver - called also enterohepatitis , histomoniasis , infectious enterohepatitis  .
 
 
 
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