A federal agency or, as appropriate, any of its operational elements.
Sources:
FIPS 200 under ORGANIZATION

  An organization that coordinates the operation of one or more processing sites.
Sources:
NIST SP 800-82r3 under Enterprise

  An organization with a defined mission/goal and a defined boundary, using information systems to execute that mission, and with responsibility for managing its own risks and performance. An enterprise may consist of all or some of the following business aspects: acquisition, program management, financial management (e.g., budgets), human resources, security, and information systems, information and mission management.
Sources:
NIST SP 800-30 Rev. 1 under Enterprise
NIST SP 800-39 under Enterprise from CNSSI 4009
NISTIR 8170 under Enterprise from CNSSI 4009

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency or, as appropriate, any of its operational elements).
Sources:
NIST SP 800-128 under Organization from FIPS 200 - Adapted
NIST SP 800-30 Rev. 1 under Organization from FIPS 200 - Adapted

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency, or, as appropriate, any of its operational elements).
Sources:
NIST SP 800-137 under Organization from FIPS 200 - Adapted
NISTIR 7693 under Organization

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency or, as appropriate, any of its operational elements). See Enterprise.
Sources:
NIST SP 800-39 under Organization from FIPS 200 - Adapted
NISTIR 8170 under Organization from FIPS 200 - adapted

  An entity of any size, complexity, or positioning within an organizational structure.
Sources:
NIST SP 800-171r3 from FIPS 200 - adapted
NIST SP 800-172 from FIPS 200 - Adapted
NIST SP 800-172A from FIPS 200 - Adapted

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency, private enterprises, academic institutions, state, local, or tribal governments, or as appropriate, any of its operational elements).
Sources:
NIST SP 800-128 from FIPS 200 - Adapted

  Group of people and facilities with an arrangement of responsibilities, authorities, and relationships.
Sources:
NIST SP 800-160v1r1 from ISO/IEC/IEEE 15288:2015, ISO 9000:2015

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency, or, as appropriate, any of its operational elements). See enterprise.
Sources:
CNSSI 4009-2015

  An organization with a defined mission/goal and a defined boundary, using information systems to execute that mission, and with responsibility for managing its own risks and performance. An enterprise may consist of all or some of the following business aspects: acquisition, program management, financial management (e.g., budgets), human resources, security, and information systems, information and mission management.
Sources:
CNSSI 4009-2015 under enterprise

  An organization with a defined mission/goal and a defined boundary, using systems to execute that mission, and with responsibility for managing its own risks and performance. An enterprise may consist of all or some of the following business aspects: acquisition, program management, human resources, financial management, security, and systems, information and mission management. See organization.
Sources:
NIST SP 800-37 Rev. 2 under enterprise from CNSSI 4009-2015
NIST SP 800-53 Rev. 5 under enterprise from CNSSI 4009-2015

  An entity of any size, complexity, or positioning within an organizational structure (e.g., federal agencies, private enterprises, academic institutions, state, local, or tribal governments, or as appropriate, any of their operational elements).
Sources:
NIST SP 800-37 Rev. 2 from FIPS 200 - adapted

  An entity of any size, complexity, or positioning within an organizational structure (e.g., a federal agency or, as appropriate, any of its operational elements). This publication is intended to provide recommendations for organizations that manage their own networks (e.g., that have a chief information officer).
Sources:
NIST SP 1800-16B under Organization from NIST SP 800-39
NIST SP 1800-16C under Organization from NIST SP 800-39
NIST SP 1800-16D under Organization from NIST SP 800-39

  An entity of any size, complexity, or positioning within an organizational structure, including federal agencies, private enterprises, academic institutions, state, local, or tribal governments, or as appropriate, any of their operational elements.
Sources:
NIST SP 800-53 Rev. 5 from FIPS 200 - Adapted
NIST SP 800-53A Rev. 5 from FIPS 200 - Adapted
NIST SP 800-53B from FIPS 200 - Adapted

  An entity of any size, complexity, or position within a larger organizational structure (e.g., a federal agency or company).
Sources:
NIST SP 800-221

  A top-level organization with unique risk management responsibilities based on its position in the hierarchy and the roles and responsibilities of its officers.
Sources:
NISTIR 8286 under Enterprise

  An entity of any size, complexity, or positioning within a larger organizational structure (e.g., a federal agency or a company).
Sources:
NISTIR 8286 under Organization