Colon

Colon refers to two main senses: the part of the digestive system known as the large intestine, and a punctuation mark used in writing.

Anatomy: The colon is the final section of the large intestine, extending from the ileocecal valve to the rectum and averaging about 1.5 meters in adults. It is divided into four segments: ascending, transverse, descending, and sigmoid.

Functions and clinical notes: Primary roles include absorption of water and electrolytes, and the formation and temporary storage of feces. The colon also hosts gut microbiota that ferment indigestible carbohydrates. Common diseases affecting the colon include diverticulosis, inflammatory bowel diseases such as ulcerative colitis and Crohn's disease with colonic involvement, and colorectal cancer. Screening with colonoscopy is a common method for early detection and prevention.

Punctuation: The colon is a punctuation mark consisting of two equally sized dots stacked vertically. It is used to introduce lists, explanations, quotations, or to separate clauses and to signal time, ratios, or subtitles in titles.

Etymology and usage notes: The term colon derives from Latin colon, from Greek kolon, meaning a clause or part; the name in anatomy reflects its role as a segment of the gut, while in punctuation it denotes a pause or elaboration.