Uniform Resource Name
A URI--that is, a string--which names a resource. URLs in contrast tell us where to find a resource, i.e. its location. RFC 2141 has the URN of "urn:ietf:RFC:2141", and the URL "http://www.ietf.org/rfc2141.txt ". It's this RFC, incidentally, which defines URNs.
[ Category Acronym ]