Hardware, software, and relevant documentation for an information system at a given point in time.
Sources:
CNSSI 4009-2015

  See control baseline.
Sources:
NIST SP 800-37 Rev. 2
NIST SP 800-53 Rev. 5
NIST SP 800-53A Rev. 5

  The set of controls that are applicable to information or an information system to meet legal, regulatory, or policy requirements, as well as address protection needs for the purpose of managing risk.
Sources:
NIST SP 800-37 Rev. 2 under control baseline

  Predefined sets of controls specifically assembled to address the protection needs of groups, organizations, or communities of interest. See privacy control baseline or security control baseline.
Sources:
NIST SP 800-53 Rev. 5 under control baseline from NIST SP 800-53B
NIST SP 800-53A Rev. 5 under control baseline from NIST SP 800-53B

  The set of security and privacy controls defined for a low-impact, moderate-impact, or high-impact system or selected based on the privacy selection criteria that provide a starting point for the tailoring process.
Sources:
NIST SP 800-53B under control baseline from FIPS 200 - Adapted

  Hardware, software, databases, and relevant documentation for an information system at a given point in time.
Sources:
NIST SP 800-161r1 from CNSSI 4009-2015

  Formally approved version of a configuration item, regardless of media, formally designated and fixed at a specific time during the configuration item’s life cycle.
Sources:
NIST SP 800-160v1r1 from IEEE Std. 828-2012

  Hardware, software, databases, and relevant documentation for an information system at a given point in time.
Sources:
NISTIR 7622 under Baseline