Kilocycle per second is an old measurement unit to express the frequency of a signal or wave. It is also known as kilohertz. However, in modern times, this unit is rarely used, and it has been replaced by more commonly used terms like megahertz and gigahertz, to express higher frequencies. Megahertz refers to one million cycles per second, while gigahertz refers to one billion cycles per second. The term hertz is also commonly used to express the frequency of a signal or wave. It refers to one cycle per second. Therefore, while kilocycle per second may not be commonly used anymore, there are various other terms available to express the frequency of a signal.