chickenpox or chicken pox
n.
An acute contagious disease, primarily of children, that is caused by the varicella-zoster virus and characterized by skin eruptions, slight fever, and malaise. Also called varicella.
A mild but highly contagious disease, caused by a virus and characterized by slight fever and the eruption of blisters on the skin. Chicken pox is classified as a disease of childhood, although it can occur in adults.
Note: Children who have had chicken pox are immune to future infection by the virus that causes it.