Skip to Content

Identifiers: Quick Reference

These guidance notes were originally published at

Glossary of terms

(this page is heavily influenced by work done by Acuity Unlimited for the JISC)

Term Meaning Notes
Identifier A token (usually a number or a string of characters) used to refer to an entity (anything which can be referred to)  
Referent The entity pointed to by the identifier This entity could be a digital object such as the file containing a research paper, or a physical object such as an item in a museum collection, or a person or organisation, or it could even be an abstract concept such as a 'learning outcome'
Minting The process of creating a new identifier, and of linking it to its referent This process which will benefit from careful consideration of how the resulting identifier will be managed and used
Resolution The process of retrieving the referent for a given identifier This might be a digital object such as a file or photo, or it might be a proxy for this such as a metadata record describing an entity.
Co-referent Identifiers are said to be 'co-referent' when they point to the same entity. An example of where this concept is expressed is 'owl:sameAs' from the Web Ontology Language (OWL) specification. An example of a service which identifies and exposes co-references is
Actionable Generally means an identifier which can be 'clicked' on to retrieve either a representation of the referent or metadata about it.  
Persistent Identifier (PID) An identifier which:
  • will always point to the same thing
  • can be relied upon to continue to exist over time

Persistent identifiers are also generally assumed to be persistently actionable.

Universally Unique Identifier (UUID) An identifier which is guaranteed to be globally unique  
Globally Unique Identifier (GUID) Typically, a synonym for a UUID, often referring to Microsoft's implementation of the UUID standard.  
Uniform Resource Identifier (URI) A Uniform Resource Identifier is a string of characters used to identify a name or a resource on the Internet. Such identification may enable interaction with representations of the resource over a network (typically the World Wide Web) using specific protocols. Schemes specifying a concrete syntax and associated protocols define each URI. URLs and URNs are both kinds of URI. Examples of URIs on the web are identifiers starting with "http:" or "mailto:".
HTTP URI A URI whose retrieval mechanism is HTTP. Typically this is for the purposes of allowing practices linking data on the web using W3C standards such as RDF, SKOS and OWL.  
Uniform Resource Locator (URL) A kind of URI that specifies where an identified web resource is available and the mechanism for retrieving it. Eg, URL specifies an address on the World Wide Web whose retrieval mechanism is specified by HTTP.  

Types of identifier commonly used in an HE context

Type Description Notes
URI URI is the identifier mechanism used by the Web An HEI will typically own its own domain and mint its own URIs.
DOI DOIs, or Digital Object Identifiers, are commonly used in the HE context to identify published articles in academic journals. DOIs are managed within a federation of agencies, a business arrangement which provides a degree of resilience and confidence in the persistence of DOIs In this context, DOIs are typically minted by a publisher via a Registration Agency, which charges a fee.


[...] There is a useful

[...] There is a useful glossary of terms available from UKOLN: [...]

Identifiers « Briefing Paper for eResearch & IE Call – 10/2010

[...] [3] Identifiers: Quick

[...] [3] Identifiers: Quick Reference: [...]

Appendix C: Identifiers « Infrastructure for Education and Research

[...] [1]

[...] [1] [2] [3] [...]

What are Persistent Identifiers? « JISC consultation on identifiers 2010

Dr. Radut | technical_resources