GPU usage indicates how much the graphics processing unit (GPU) of a system is being utilized at a given moment. Measured in percentage, it reflects the intensity of tasks such as 3D rendering, video editing, or machine learning workloads. High usage suggests demanding processes or heavy system load, while low usage indicates available, unused resources. Monitoring GPU usage is essential for performance optimization, troubleshooting, and efficient resource management, especially in graphics-intensive or computationally heavy applications.