An information system used to control industrial processes such as manufacturing, product handling, production, and distribution. Industrial control systems include supervisory control and data acquisition systems used to control geographically dispersed assets, as well as distributed control systems and smaller control systems using programmable logic controllers to control localized processes.
Sources:
NIST SP 800-30 Rev. 1 under Industrial Control System from NIST SP 800-39
NIST SP 800-39 under Industrial Control System

  General term that encompasses several types of control systems, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other control system configurations such as programmable logic controllers (PLC) often found in the industrial sectors and critical infrastructures. An ICS consists of combinations of control components (e.g., electrical, mechanical, hydraulic, pneumatic) that act together to achieve an industrial objective (e.g., manufacturing, transportation of matter or energy).
Sources:
NIST SP 800-37 Rev. 2 under industrial control system from NIST SP 800-82 Rev. 2

  General term that encompasses several types of control systems, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other control system configurations such as programmable logic controllers (PLC) found in the industrial sectors and critical infrastructures. An industrial control system consists of combinations of control components (e.g., electrical, mechanical, hydraulic, pneumatic) that act together to achieve an industrial objective (e.g., manufacturing, transportation of matter or energy).
Sources:
NIST SP 800-53 Rev. 5 under industrial control system from NIST SP 800-82 Rev. 2

  An information system used to control industrial processes such as manufacturing, product handling, production, and distribution.
Sources:
NIST SP 1800-10B under Industrial Control Systems from NIST SP 800-30 Rev. 1

  a general term that encompasses several types of control systems, including supervisory control and data acquisition (SCADA) systems, distributed control systems (DCS), and other control system configurations such as Programmable Logic Controllers (PLC) often found in the industrial sectors and critical infrastructures.
Sources:
NISTIR 8074 Vol. 2 under Industrial Control System from NIST SP 800-82 Rev. 2