Varicella is a very contagious virus that causes flu-like symptoms and an itchy rash. Another name for varicella is chickenpox. No matter what you call it, it's no fun.
If your doctor mentions getting a varicella vaccine, now you'll know she's talking about giving you a shot to help prevent chickenpox. This medical term comes from Latin, and it's closely related to variola, or "smallpox." Both words share the root varius, "speckled or spotted." It's the spots, or small blisters, that make this illness so distinctive. They're obvious — and very itchy — evidence that you've come down with varicella.