noun
Etymology: probably translation of French cinquième maladie ; so called because it was the fifth of five exanthematous childhood diseases known at the time of its description (1928)
: an acute eruptive disease especially of children that is caused by a parvovirus (genus Erythrovirus ) and is first manifested by a blotchy red rash on the cheeks followed by a maculopapular rash on the extremities and that is usually accompanied by fever and malaise — called also erythema infectiosum