contingency

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. An event that may occur but that is not likely or intended; a possibility.
2. n. A possibility that must be prepared for; a future emergency.
3. n. The condition of being dependent on chance; uncertainty.
4. n. Something incidental to something else.

Century Dictionary and Cyclopedia

1. n. The mode of existence of that which is contingent; the possibility that that which happens might not have happened; that mode of existence, or of coming to pass, which does not involve necessity; a happening by chance or free will; the being true of a proposition which would not under all circumstances be true.
2. n. A casualty; an accident; a fortuitous event, or one which may or may not occur.
3. n. A touching; a falling together; contact: as, “the point of contingency,”
4. n. In biometry, a method of studying statistically biological data that do not admit of numerical expression.

Wiktionary

1. n. a conditional response plan made in preparation for various future circumstances including the unanticipated.
2. n. The quality of being contingent; unpredictability.
3. n. A possibility; something which may or may not happen.
4. n. An amount of money which a party to a contract has to pay to the other party (usually the supplier of a major project to the client) if he or she does not fulfill the contract according to the specification.

GNU Webster's 1913

1. n. Union or connection; the state of touching or contact.
2. n. The quality or state of being contingent or casual; the possibility of coming to pass.
3. n. An event which may or may not occur; that which is possible or probable; a fortuitous event; a chance.
4. n. An adjunct or accessory.
5. n. A certain possible event that may or may not happen, by which, when happening, some particular title may be affected.

WordNet 3.0

1. n. a possible event or occurrence or result
2. n. the state of being contingent on something