system clock (n)~ The electronic circuit in a computer that generates a steady stream of timing pulses—the digital signals that synchronize every operation. The system clock signal is precisely set by a quartz crystal typically at a specific frequency between 1 and 50 megahertz. The clock rate of a computer is one of the prime determinants of its overall processing speed and it can go as high as the other components of the computer allow. system color (n)~ A color that is defined by the operating system for a specific type of monitor and video adapter and that is associated with a specific part of the user interface such as a window title or a menu.