A nanosecond is a unit of time equal to one billionth of a second, or 10^-9 seconds. It is commonly used in fields like electronics and telecommunications to measure the speed of data transmission and processing. For example, the time it takes for light to travel a distance of about 30 centimeters is approximately one nanosecond. In computing, nanoseconds are crucial for understanding the performance of processors and memory. Modern computer operations can occur in nanoseconds, allowing for rapid calculations and data handling. This precision is essential for technologies such as fiber optics and high-speed internet.