Configuration Item (CI) definition in Computer Security terms:
Definition(s): An aggregation of information system components that is designated for configuration management and treated as a single entity in the configuration management process.
Source(s): CNSSI 4009-2015 (NIST SP 800-53 Rev. 4)
NIST SP 800-53 Rev. 4
NIST SP 800-128
reference: CSRC Glossary