Fibroid: A common benign tumor of the uterus. Fibroids can be present without symptoms. However, in about 25 percent of women, fibroids cause symptoms such as prolonged or heavy menstrual bleeding, pelvic pressure or pain, and, in rare cases, reproductive dysfunction. Drugs that manipulate the levels of steroid hormones can be effective in treating fibroids, but side effects limit their long-term use. Fibroids may be removed if they cause discomfort or if they are associated with uterine bleeding. In addition to hysterectomy and abdominal myomectomy, various minimally invasive procedures have been developed to remove or diminish the size of fibroids. Also known as leiomyoma and myoma of the uterus.