A disorder characterized by the presence of dilated veins in the rectum and surrounding area.
Definition (MEDLINEPLUS)
Hemorrhoids are swollen, inflamed veins around the anus or lower rectum. They are either inside the anus or under the skin around the anus. They often result from straining to have a bowel movement. Other factors include pregnancy, aging and chronic constipation or diarrhea.
Hemorrhoids are very common in both men and women. About half of all people have hemorrhoids by age 50. The most common symptom of hemorrhoids inside the anus is bright red blood covering the stool, on toilet paper or in the toilet bowl. Symptoms usually go away within a few days.
If you have rectal bleeding you should see a doctor. You need to make sure bleeding is not from a more serious condition such as colorectal or anal cancer. Treatment may include warm baths and a cream or other medicine. If you have large hemorrhoids, you may need surgery and other treatments.
NIH: National Institute of Diabetes and Digestive and Kidney Diseases
Definition (NCI)
An enlarged or swollen blood vessel, usually located near the anus or the rectum.
Definition (MSH)
Swollen veins in the lower part of the RECTUM or ANUS. Hemorrhoids can be inside the anus (internal), under the skin around the anus (external), or protruding from inside to outside of the anus. People with hemorrhoids may or may not exhibit symptoms which include bleeding, itching, and pain.