roseola infantum
noun
roseola in·fan·tum -in-ˈfan-təm 
: a mild virus disease of infants and children marked by fever lasting usually three days followed by an eruption of rose-colored spots and caused by a herpesvirus (species Human herpesvirus 6 of the genus Roseolovirus)
Word History
Etymology
borrowed from New Latin, "roseola of infants"
First Known Use
circa 1935, in the meaning defined above
Medical Definition
roseola infantum
noun
roseola in·fan·tum -in-ˈfant-əm
: a mild virus disease of infants and children that is characterized by fever lasting three days followed by an eruption of rose-colored spots and is caused by a herpesvirus (species Human herpesvirus 6 of the genus Roseolovirus)
called also exanthema subitum, exanthem subitum