K

key()

A function in an expression used in XSLT that selects the node with the given unique key identifier. The first parameter names a key set, as defined using the Key element.

key-field

A field with the special property that it must contain a different (unique) value in every record in the table. It is especially useful in a relation database, because it allows information stored across a number of tables to be unambiguously linked.

keyword

A word appearing in markup that identifies the purpose of the tag, or some part of it. For example, 'IGNORE' is a keyword that identifies a portion of the document to be ignored.