Generally speaking, you can define latency as the time delay between the cause and the effect of some change in the system being observed. In a point to point communication, you calculate latency as the time it takes to get a response from the system. When you involve many services in a single workflow then the latency is the sum of all the response times.
How can you avoid latency in microservices? Learn more about it with this presentation about Asynchronous Microservices.