"Disease caused by bacteria of the genus Actinomyces in cattle, other animals, or humans, typically characterized by the formation of nodular suppurating abscesses, most commonly in the region of the head and neck; an instance or type of this", Late 19th cent.; earliest use found in The Nineteenth Century. From actino- + mycosis, after German Actinomykose.[actinomycosis etymology, actinomycosis origin, 英语词源]