CPU Usage refers to the percentage of time the Central Processing Unit (CPU) is actively processing tasks. It indicates how much of the CPU's capacity is being utilized by running applications and processes. High CPU usage can lead to slower performance, as the CPU may struggle to handle multiple tasks simultaneously. Monitoring CPU Usage is essential for maintaining system performance. Tools like Task Manager on Windows or Activity Monitor on macOS can help users track CPU usage in real-time. Keeping an eye on this metric can help identify resource-heavy applications and optimize overall system efficiency.