cross-reference

thumb|A cross-reference for varuce (varices|varice) in [[Andrew Boorde's The Breviarie of Health (1502)]]

A cross-reference (sometimes abbreviated as xref) is an instance within a document which refers the reader to related or synonymous information elsewhere, usually within the same work. To cross-reference is to make such connections. Cross-references typically link to a related topic. Cross-referencing is usually employed by readers to either verify claims made by an author or to find information on a topic of interest. 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.