any bacterium of the group Actinomycetes, usually filamentous in form
Word origin
C20: from actino- + -mycete
actinomycete in American English
(ˌæktəˌnoʊˈmaɪˌsit; ˌæktəˌnoʊmaɪˈsit)
noun
any of various bacteria (order Actinomycetales) with a branching, filamentous structure; esp., any of a family (Actinomycetaceae) of Gram-positive bacteria that are pathogenic to humans and animals