The portion of a computer that generates a repetitive, high-frequency electrical signal so as to precisely synchronize computer events and operations. The rate at which the clock generates signals—known as the clock rate—is usually measured in megahertz, or millions of cycles per second. The term "speed" when used to describe a processor is synonymous with "clock" or "clock rate." As of this writing, PowerPC and Intel Pentium processors are capable of clock rates of up to 200 MHz. This is impressive when you consider that that clock rate of the original Intel 8088 chip used in the first IBM PC had a clock rate of 4.77 MHz. Also called a clock generator.