onychomycosis

noun
on·​y·​cho·​my·​co·​sis | \ -mī-ˈkō-səs How to pronounce onychomycosis (audio) \
plural onychomycoses\ -​ˌsēz How to pronounce onychomycoses (audio) \

Medical Definition of onychomycosis

: a fungal disease of the nails