A microsecond is a unit of time equal to one-millionth of a second, or 0.000001 seconds. It is commonly used in fields like electronics and computing, where precise timing is crucial. For example, the speed of a computer's processor can be measured in microseconds, indicating how quickly it can perform tasks. In everyday life, microseconds are often too short to notice, but they play a significant role in technology. For instance, the response time of a computer mouse or the refresh rate of a monitor can be measured in microseconds, affecting how smoothly we interact with devices.