A synonym for delay, is the amount of time it takes to send information from one point to the next. Latency is usually measured in milliseconds (ms). It’s also referred to (during speed tests) as a ping rate.
Latency is measured by sending a packet that is returned to the sender and the round-trip time is considered the latency.
Latency’s effects depend on observers, but most will perceive obvious latency around 100-120 milliseconds. Communications will start to break down around 250-300ms.
Recommended latency value is <100 ms.