CUI registry definition in Computer Security terms:
Definition(s): The online repository for all information, guidance, policy, and requirements on handling CUI, including all issuances by the CUI Executive Agent. Among other information, the CUI Registry identifies approved CUI categories and subcategories, provides general descriptions for each, identifies the basis for controls, and sets out procedures for the use of CUI, including but not limited to marking, safeguarding, transporting, disseminating, reusing, and disposing of the information.
Source(s): NIST SP 800-171 (Updates to version published June 2015)
reference: CSRC Glossary