Wiktionary
n. (context anatomy English) the S-shaped section of the large intestine between the descending colon and the rectum
WordNet
n. the s-shaped curve between the descending colon and the rectum [syn: sigmoid flexure]
Wikipedia
The sigmoid colon (pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about 40 cm in length. The loop is typically shaped like a Greek letter sigma (ς) or Latin letter S (thus sigma + -oid). This part of the colon normally lies within the pelvis, but on account of its freedom of movement it is liable to be displaced into the abdominal cavity.
Usage examples of "sigmoid colon".
One male summer complaint found Doggy performing a sigmoidoscopy, that is, an examination of the rectum and sigmoid colon.
Indeed (as I'd rather hoped) the little mystery so intrigued him that he gave over his heavy-breathed inspection of my sigmoid colon.