What is a clock cycle?

[Saint71]

Could someone explain in laymans terms what exactly a clock cycle is and how it works and relates to processors.

 

[Nitestick]

clock cycle=a processor cycle, in other words a set of things the processor does. number of clock cycles per second=frequency i.e in ghz. a 2.0ghz processor has 2 billion clock cycles per second, so it can perform a given set of things 2 billion times per second