key n. an object used for selection during retrieval. See association list, property list, and hash table. Also, see Section 17.1 (Sequence Concepts).

keyword n. 1. a symbol the home package of which is the KEYWORD package. 2. any symbol, usually but not necessarily in the KEYWORD package, that is used as an identifying marker in keyword-style argument passing. See lambda. 3. Idiom. a lambda list keyword.

keyword parameter n. A parameter for which a corresponding keyword argument is optional. (There is no such thing as a required keyword argument.) If the argument is not supplied, a default value is used. See also supplied-p parameter.

keyword/value pair n. two successive elements (a keyword and a value, respectively) of a property list.

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