colon

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A punctuation mark ( : ) used after a word introducing a quotation, an explanation, an example, or a series and often after the salutation of a business letter.
2. n. The sign ( : ) used between numbers or groups of numbers in expressions of time (2:30 A.M.) and ratios (1:2).
3. n. A section of a metrical period in quantitative verse, consisting of two to six feet and in Latin verse having one principal accent.
4. n. The section of the large intestine extending from the cecum to the rectum.
5. n. See Table at currency.

Century Dictionary and Cyclopedia

1. n. In ancient Grammar and rhetoric, one of the larger or principal divisions of a sentence or period; a long clause, or a group of minor clauses or commata. See comma, 1.
2. n. In ancient prosody, one of the members or sections of a rhythmical period, forming an uninterrupted sequence of feet, united under a principal ictus or beat: sometimes called a series. A colon could not consist of more than 6 trisemic, 5 tetrasemic or pentasemic, or 3 hexasemic feet. It usually corresponded to one of the lines of a modern couplet, triplet, or stanza, or formed part only of a longer line. A pure colon is a colon consisting of feet of one kind only; a mixed colon is composed of feet of different kinds. See period.
3. n. In paleography, a long clause or group of clauses, or a series of words of about the average length of such a group, estimated as approximately equal to a dactylic hexameter in extent—that is, as containing from 12 to 17 syllables. A colon in this sense was frequently written as a separate line in manuscript, and served to measure the length of a book or treatise. See colometry and epos.
4. n. A mark of punctuation formed by two dots like periods placed one above the other (:), used to mark a discontinuity of grammatical construction greater than that indicated by the semicolon and less than that indicated by the period. The colon is commonly used to emphasize a close connection in thought between two clauses of which each forms a complete sentence, and which might with grammatical propriety be separated by a period; to separate a clause which is grammatically complete from a second which contains an illustration or amplification of its meaning: thus, in this work illustrative clauses introduced by “as” are separated from the definition by a colon; to introduce a formal statement, an extract, a speech in a dialogue, etc. Originally it was the mark of the termination of the grammatical or paleographic division called by the same name, and it is now frequently used to mark off metrical periods in prose intended for chanting.
5. n. In anatomy, a portion of the intestinal tract, the so-called “large” as distinguished from the “small” intestine, continuous from the ileum to the rectum; the great gut, beginning at the cæcum and ending in the sigmoid flexure. In man and mammals generally the colon is distinguished from the preceding small intestine by its greater caliber, and by its sacculation, due to the particular distribution of its circular muscular fibers, which constrict it at some places and allow it to bulge out at others, making a series of pouch-like expansions. It may also present continuous bands of longitudinal fibers, or lengthwise constrictions, so that the cross-section is not circular. The colon may not he distinguishable in size or appearance from the rest of the intestine, as in birds, where its commencement is marked only by the presence of a cæcum or of two cæca; and when these arc wanting, there is no distinction. In man the course and situation of the colon are definite, owing to the binding of the gut in place by the mesocolon and gastrocolic omentum. Beginning at the cæcum and ascending by the right kidney, it passes under the concave surface of the liver and the bottom of the stomach to the spleen; thence descending by the left kidney, it passes in the form of an S to the upper part of the sacrum, where it becomes the rectum. The parts of the colon are designated according to their position or direction: as, the right lumbar or ascending colon; the arch of the colon, or transverse colon; the left lumbar or descending colon; and the sigmoid flexure, or left iliac colon. See cuts under alimentary and intestine.
6. n. In entomology, the second portion of an insect's intestine, generally broader than the preceding portion or ileum. It may be straight or convoluted, terminating at the anal opening, or separated from it by a short rectum.
7. n. The silver peso or dollar of Costa Rica, of the value of 46½ cents or 100 centavos.

Wiktionary

1. n. grammar The punctuation mark ":".
2. n. rare The triangular colon (especially in context of not being able to type the actual triangular colon).
3. n. A rhetorical figure consisting of a clause which is grammatically, but not logically, complete.
4. n. anatomy Part of the large intestine; the final segment of the digestive system, after (distal to) the ileum and before (proximal to) the anus

GNU Webster's 1913

1. n. (Anat.) That part of the large intestines which extends from the cæcum to the rectum. [See Illust. of digestion.]
2. n. (Gram.) A point or character, formed thus [:], used to separate parts of a sentence that are complete in themselves and nearly independent, often taking the place of a conjunction.

WordNet 3.0

1. n. the part of the large intestine between the cecum and the rectum; it extracts moisture from food residues before they are excreted
2. n. a punctuation mark (:) used after a word introducing a series or an example or an explanation (or after the salutation of a business letter)
3. n. the basic unit of money in El Salvador; equal to 100 centavos
4. n. a port city at the Caribbean entrance to the Panama Canal
5. n. the basic unit of money in Costa Rica; equal to 100 centimos