varicella /ˌvær.ɪˈsɛl.ə/ noun2 •An acute, highly contagious pathogenic disease caused by the varicella zoster virus, primarily affecting children and characterized by a widespread eruptive skin rash of itchy blisters;chicken pox •Any of various other eruptive diseases, such as swinepox, hives, and varioloid. formsvaricellae · varicellas