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Cross-reference
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Look up <i>cross-reference</i> in Wiktionary, the free dictionary. <p>The term cross-reference (abbreviation: xref) can refer to either: </p> <ul><li>An instance within a <a href="/facts/Document/H4Hdxu91">document</a> which refers to related information elsewhere in the same document. In both printed and online dictionaries cross-references are important because they form a network structure of relations existing between different parts of data, dictionary-internal as well as dictionary external.</li> <li>In an <a href="/facts/Index_(publishing)/amN9DI6s">index</a>, a cross-reference is often denoted by <i>See also</i>. For example, under the term <i>Albert Einstein</i> in the index of a book about Nobel Laureates, there may be the cross-reference <i>See also: Einstein, Albert</i>.</li> <li>In <a href="/facts/Hypertext/qD8ozxSb">hypertext</a>, cross-references take the form of "live" references within the text that, when activated by <a href="/facts/Point_and_click/YvGz3Bah">mouse click</a>, <a href="/facts/Touch_user_interface/kvoawM0g">touch</a>, voice command or <a href="/facts/Accessibility/hp9gz5GK">other means</a>, immediately makes available the referenced content, which might be a different part of the same document, or another document entirely.</li> <li>In programming, "cross-referencing" means the listing of every file name and line number where a given <a href="/facts/Identifier/pPaQPLhj">named identifier</a> occurs within the program's <a href="/facts/Source_tree/o9J6Jv23">source tree</a>.</li> <li>In a <a href="/facts/Relational_database_management_system/pEKGmJLy">relational database management system</a>, a table can have an xref as prefix or suffix to indicate it is a <a href="/facts/Cross-reference_table/9IXU8WEN">cross-reference table</a> that joins two or more tables together via <a href="/facts/Primary_key/veT9mAbo">primary key</a>.</li></ul>