Varicella (chickenpox) definition - Healthy Kids and Pediatrics - health and medical information produced by doctors

Varicella (chickenpox): A highly infectious viral disease, known familiarly as chickenpox. (In many countries, this disease is always called "varicella.")

Chickenpox has nothing at all to do with chicken. The name was meant to distinguish this "weak" form of the pox from smallpox. "Chicken" is used here, as in "chickenhearted," to mean weak or timid. The "pox" of chickenpox is no major matter unless it becomes infected (through scratching) or occurs in an immunodeficient person.