Short Answer
An ORCID is a persistent digital identifier (Open Researcher and Contributor ID) to uniquely identify scientific and other academic authors and contributors.
Detailed Answer
An ORCID is a persistent digital identifier (Open Researcher and Contributor ID) to uniquely identify scientific and other academic authors and contributors. ORCID is also the name of a non-profit organization that provides ORCIDs along services for this identifier, learn more here https://orcid.org/ and here https://en.wikipedia.org/wiki/ORCID.