A CURIE (short for Compact URI) defines a generic, abbreviated syntax for expressing URIs. It is an abbreviated URI expressed in CURIE syntax, and may be found in both XML and non-XML grammars. A CURIE may be considered a datatype.
An example of CURIE syntax:
The square brackets may be used to prevent ambiguities between CURIEs and regular URIs, yielding so-called safe CURIEs.
QNames (the namespace prefixes used in XML) often are used as a CURIE, and may be considered a type of CURIE. CURIEs, as defined by the W3C, will be better defined and may include checking. Unlike QNames, the part of a CURIE after the colon does not need to conform to the rules for XML element names.
The first W3C Working Draft of CURIE syntax was released 7 March 2007.
The final recommendation was released 16 January 2009 
This example is based on one from the W3C Working Draft 7 March 2007, using a QName syntax within XHTML.
<html xmlns:wiki="http://en.wikipedia.org/wiki/"> <head>...</head> <body> <p> Find out more about <a href="[wiki:Biome]">biomes</a>. </p> </body> </html>
- The definition ("<html xmlns:wiki="http://en.wikipedia.org/wiki/">") is highlighted in yellow
- The CURIE ("[wiki:Biome]") is highlighted in green
- W3C Candidate Recommendation 16 January 2009