contraction

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act of contracting or the state of being contracted.
• noun A word, as won't from will not, or phrase, as o'clock from of the clock, formed by omitting or combining some of the sounds of a longer phrase.
• noun The formation of such a word.
• noun Physiology The shortening and thickening of functioning muscle or muscle fiber.
• noun A period of decreased business activity.

from The Century Dictionary.

• noun The act of drawing together or shrinking; the condition of becoming smaller in extent or dimensions through the nearer approach to one another of the parts; the state of being contracted; a decrease in volume, bulk, or dimensions, as from loss of heat.
• noun The act of making short, of abridging, or of reducing within a narrower compass by any means; the act of lessening or making smaller in amount; the state of being so lessened; reduction; diminution; abridgment: as, a contraction of the currency.
• noun Specifically A shortening of a word in pronunciation or in writing: as, can't is a contraction of cannot.
• noun In ancient prosody, the use of a single long time or syllable in place of two short times.
• noun The act of making a contract; the state of being under a contract, especially one of marriage.
• noun In surgery, an abnormal and permanent alteration in the relative position and forms of parts, arising from various causes, as in ankylosis, distortion, clubfoot, wryneck, etc.
• noun In mathematics, any device for abridging the mechanical labor of making calculations by diminishing the number of characters written down.
• noun The act or process of contracting or acquiring: as, the contraction of a debt.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act or process of contracting, shortening, or shrinking; the state of being contracted.
• noun (Math.) The process of shortening an operation.
• noun The act of incurring or becoming subject to, as liabilities, obligation, debts, etc.; the process of becoming subject to.
• noun Something contracted or abbreviated, as a word or phrase; -- as, plenipo for plenipotentiary; crim. con. for criminal conversation, etc.
• noun (Gram.) The shortening of a word, or of two words, by the omission of a letter or letters, or by reducing two or more vowels or syllables to one; as, ne'er for never; can't for can not; don't for do not; it's for it is.
• noun obsolete A marriage contract.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A reversible reduction in size.
• noun economics A period of economic decline or negative growth.
• noun biology A shortening of a muscle when it is used.
• noun medicine A strong and often painful shortening of the uterine muscles prior to or during childbirth.
• noun linguistics A process whereby one or more sounds of a free morpheme (a word) are lost or reduced, such that it becomes a bound morpheme (a clitic) that attaches phonologically to an adjacent word.
• noun A word with omitted letters replaced by an apostrophe, usually resulting from the above process.
• noun medicine Contracting a disease.
• noun phonetics Syncope, the loss of sounds from within a word.
• noun The acquisition of something, generally negative.
• noun medicine A distinct stage of wound healing, wherein the wound edges are gradually pulled together.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the process or result of becoming smaller or pressed together
• noun (physiology) a shortening or tensing of a part or organ (especially of a muscle or muscle fiber)
• noun a word formed from two or more words by omitting or combining some sounds
• noun the act of decreasing (something) in size or volume or quantity or scope