A millisecond is a unit of time equal to one-thousandth of a second. It is commonly used in various fields, including science, technology, and sports, to measure very short durations. For example, in computing, the speed of processors is often measured in milliseconds to indicate how quickly they can perform tasks. In everyday life, milliseconds can be crucial in activities like car racing or video gaming, where even the smallest delay can affect performance. Understanding milliseconds helps in appreciating the precision required in high-speed activities and technologies, such as high-frequency trading in finance or digital communications.