Latency (also called "ping") is the more technical term for lag, which is when you experience response delays during gaming. High latency means more lag, which everyone knows makes gaming way less enjoyable. Low latency means less lag and smoother gameplay.
Generally, when you test your ping, an acceptable number is anywhere around 40 to 60 milliseconds (ms) or lower, while a speed of over 100 ms will usually mean a noticeable lag in gaming. Essentially, you want the latency from your gaming device to the internet server to be as close to 0 ms as possible, as this means it takes little to no time for one device to respond to another.
See Also
Ping Jitter Test
