n 1  cap  :  a genus of filamentous or rod-shaped gram-positive bacteria of the family Actinomycetaceae that includes usu. commensal and sometimes pathogenic forms inhabiting mucosal surfaces esp. of the oral cavity - compare ACTINOMYCOSIS   2  pl  actinomyces  :  a bacterium of the genus Actinomyces ac*ti*no*my*ce*tal adj 
 
   
 
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