Xref

An Ukiyo-e image of an Oiran. Found at: http://www.artgallery.sbc.edu/ukiyoe/ecatalog.jpg/japan5.18.jpeg ...
Found on http://en.wikipedia.org/wiki/Xref

XREF

An xref represents a conceptual association between referenced resources. This association may be typed by an association definition, or it may be an untyped xref. XRefs may appear in rich text or inside the associations` field, which is a special container for XRefs pertaining to a reference. An xref is different from a crossref, because the xref ...
Found on http://www.encyclo.co.uk/local/20846

Xref

XREF is an abbreviation for Cross Reference
Found on http://www.probertencyclopaedia.com/N24.HTM
No exact match found