Latency
Noun · Development
Definitions
The time delay between a request and its response. In networking, it's the round-trip time for a packet. In user experience, it's the time between click and response. Every millisecond counts — Amazon found that 100ms of added latency cost 1% of sales.
In plain English: The delay between asking for something and getting it — how long you wait after clicking a button before something happens.