urticaria

Hives can be caused by a number of things. It can be a reaction to the piece of food you ate, the new medication you took, or irritants in the air you breathe, among other causes. Urticaria was named in the 18th century for its resemblance to the rash caused by nettle, a plant of the genus Urtica. That genus name reflects the Latin word for "nettle" and is also related to the Latin verb urere, meaning "to burn." (It's easy to see the connection here if you know that many species of nettle have stinging hairs that irritate the skin.)