Nomisma.org is a collaborative project to provide stable digital representations of numismatic concepts according to the principles of Linked Open Data. These take the form of http URIs that also provide access to reusable information about those concepts, along with links to other resources. The base format of nomisma.org is xhtml+rdfa1.1, with versions available in multiple formats.

While the URIs provided by nomisma.org are stable, the project is in progress and subject to constant expansion and ongoing correction. This is particularly the case for the information provided about each nomisma.org identifier.

The information provided by nomisma.org has been provided by a wide community of scholars and insitutions.

The project is steered by a committee currently consisting of:

• Florence Codine, BnF
• Karsten Dahman, MK Berlin
• Ethan Gruber, ANS
• Sebastian Heath, NYU ISAW
• Chris Howgego, Ashmolean Museum, University of Oxford
• Andrew Meadows, ANS
• Ulrike Peter, Berlin-Brandenburg Academy of Sciences and Humanities
• Daniel Pett, BM PAS
• Karsten Tolle, DBIS, University of Frankfurt
• David Wigg-Wolf, DAI RGK

Nomisma.org also hosts the Numismatic Description Standard

Nomisma.org focuses on URIs for concepts that are unique to numismatics or which have a distinct meaning within the discipline. Examples are:

1. http://nomisma.org/id/axis. The 'axis' is the angular relationship between the obverse and reverse of a coin.
2. http://nomisma.org/id/ephesus. The 'mint' at Ephesus. Nomisma relates this numismatic concept to other URIs such as wikipedia, Pleiades, Getty thesauri, and the British Museum.
3. http://nomisma.org/id/quinarius. Nomisma.org maintains lists of Roman and other denominations. To indicate that “quinarius” is a concept within Roman numismatics, the Dublin Core property "dcterms:isPartOf" relates this URI to http://nomisma.org/id/roman_numismatics.