A hemorrhoid, also known as a pile, is a swollen and inflamed vein in the rectum or anus that can cause discomfort, pain, and bleeding. They can be internal, located inside the rectum, or external, found under the skin around the anus. Common causes include straining during bowel movements, pregnancy, and prolonged sitting. Treatment options range from lifestyle changes and over-the-counter remedies to medical procedures in severe cases.