ORCID stands for Open Researcher and Contributor ID, which is a unique, open digital identifier that distinguishes researchers from every other researcher with the same or a similar name. It is a global, not-for-profit organization that provides a persistent digital identifier (an ORCID iD) that researchers own and control, and that distinguishes them from every other researcher. ORCID iDs are a subset of the International Standard Name Identifier (ISNI), under the auspices of the International Organization for Standardization (as ISO 27729), and the two organizations are cooperating. ORCID iDs are specified as URLs, and they are used to uniquely identify authors and contributors of scholarly communication as well as ORCIDs website and services to look up authors and their bibliographic output. ORCID is financially sustained by membership fees from organizational members who come from all sectors of the research community -- associations, funders, publishers, repositories, research organizations, facilities, and more.