The concept of network latency refers to the time delay experienced in data transmission over a network. It is measured in milliseconds and can be influenced by various factors such as distance, network congestion, and the type of connection used. Low latency is crucial for applications that require real-time communication, like online gaming and video conferencing, as it ensures a smoother user experience. Conversely, high latency can result in delays, causing disruptions and affecting the quality of service.