Latency refers to the delay or lag experienced in the processing or transmission of data within a system or over a network. Often measured in milliseconds, latency can affect various aspects of computing and communications, including the time it takes for a web page to load, the quality of video streaming, or the responsiveness in online gaming. Factors contributing to latency can range from physical distance between communicating devices, the number of intermediary nodes like routers or switches, to the efficiency of software and hardware configurations. High latency can be detrimental to user experience and system performance, making it a critical metric to monitor and optimize in real-time applications, cloud computing, and network design.