| Usually, hemorrhoids. Pathology. an abnormally enlarged vein mainly due to a persistent increase in venous pressure, occurring inside the anal sphincter of the rectum and beneath the mucous membrane (internal hemorrhoid) or outside the anal sphincter and beneath the surface of the anal skin (external hemorrhoid). |

hemorrhoid hem·or·rhoid (hěm'ə-roid')
n.
An itching or painful mass of dilated veins in swollen anal tissue.
or hemorrhoids The pathological condition in which such painful masses occur. Also called piles.
hemorrhoidal hem·or·rhoi·dal (hěm'ə-roid'l)
adj.
Of or relating to hemorrhoids.
Relating to certain arteries and veins supplying the region of the rectum and anus.