Operational technology (OT): The technology commonly found in cyber-physical systems that is used to manage physical processes and actuation through the direct sensing, monitoring and or control of physical devices, for example, motors, valves, pumps, etc. 
In a vessel these systems include: plant and machinery, RF communications, on and off board sensors and navigation systems.
Operational Technology (OT) is the hardware and software dedicated to detecting or causing changes in physical processes through direct monitoring and/or control of physical devices.
Operational technology (OT) is hardware and software that detects or causes a change through the direct monitoring and/or control of physical devices, processes and events in the enterprise. 
Operational technology (OT) is the technology that is used to operate, monitor and control the power system. 
Information Communication Technology
Industrial Automation Control System
Supervisory Control and Data Acquisition
- ↑ NCSC, UK
- ↑ Code of Practice Cyber Security for Ships, DSTL (2017)
- ↑ Gartner glossary
- ↑ ESCOM at Utilities Telecommunication Council (2016)