ulcer

ulcer
/ˈʌlsə(r); `ʌlsɚ/ n
open sore containing poisonous matter on the outside of the body or on the surface of an internal organ 溃疡: leg ulcers 腿部溃疡
    gastric ulcers 胃溃疡
    My mouth has an ulcer. 我的口腔出现了溃疡.

牛津英汉双解词典