Duty Cycle

Ran into this term while I was doing PID tuning with the VESC.

Duty cycle is the ratio of time a load or circuit is ON compared to the time the load or circuit is OFF.

• Source: https://www.fluke.com/en-us/learn/blog/electrical/what-is-duty-cycle

I thought everything is 50% duty cycle? Yes, that is how most system clocks are.