CPU utilization refers to a computer's usage of processing resources, or the amount of work handled by a CPU. Actual CPU utilization varies depending on the amount and type of managed computing tasks. Certain tasks require heavy CPU time, while others require less because of non-CPU resource requirements.
Techopedia explains CPU Utilization
CPU utilization may be used to gauge system performance. For example, a heavy load with only a few running programs may indicate insufficient CPU power support, or running programs hidden by the system monitor - a high indicator of viruses and/or malware.
CPU utilization should not be confused with CPU load.