A persistent identifier is a long-lasting reference to a digital resource.
An identifier is a label which gives a unique name to an entity: a person, place, or thing. Unlike URLs, which may break, a persistent identifier reliably points to a digital entity. An ORCID iD is an example of a persistent identifier for a person. Learn more about persistent identifiers.
You may have heard of DOIs (digital object identifiers), which are persistent identifiers for things or entities such as journal articles, books, and datasets. Crossref and DataCite are the main organizations assigning DOIs for these purposes in scholarly communication. ORCID works closely with Crossref, DataCite, and many other PID organizations to build trusted connections between iDs and other identifiers.
Learn more about the work of DataCite and Crossref, the organization identifier project, Project THOR (Technical and Human infrastructure for Open Research), and Metadata2020 (the scholarly community's group effort to advocate for richer shared metadata).