A cycle per second is a way of measuring how many times something happens in a second. Imagine you are riding on a bike and your feet are pedaling the pedals. Every time your feet go around in a full circle, that is one cycle. How many times your feet go around in a second is measured in cycles per second.
Let's say you are pedaling really fast and your feet are going around in a full circle 10 times in one second. That means you are going at a speed of 10 cycles per second. If you slow down and your feet only go around in a full circle 5 times in one second, then you are going at a speed of 5 cycles per second.
Cycle per second is also known as Hertz (Hz). It is used to measure different kinds of things that happen repeatedly in a second, like sound waves or electrical signals. The higher the cycle per second or Hertz, the faster the thing is happening.