Operational-technology, or OT, refers to the hardware and software that monitor and control physical processes such as power generation, transmission, water treatment, manufacturing lines, and industrial control systems. Unlike office IT, OT is tied to real-world equipment, so changes can affect safety, uptime, and the continuity of essential services.
OT matters in cyber security because a compromise can have physical consequences, not just data loss. Attackers may target OT to disrupt operations, alter sensor readings, or interfere with controllers, while defenders focus on network segmentation, strict access control, asset visibility, and patching where uptime allows. In utility incidents, it is important to distinguish customer portals and billing systems from OT: account-data breaches can enable fraud and phishing without indicating any impact on generation, transmission, or grid control.