Latency is the noun that belongs with latent: the stretch of time when something is already there but not showing, or not active yet. A virus can sit in latency in the body. A talent can stay in latency for years until someone asks you to use it. That is the older, more bookish sense, and it is the one tied to hidden / not yet noticeable. Though actually, the way most learners meet this word now is in computers, phones, and games. There, latency is the wait — how long a signal takes to go and come back. High latency means the picture jumps or the game feels slow; people just call it lag. The two uses share a feeling of something not yet arrived in the open, but in tech talk nobody is thinking about hidden disease. They mean delay. It is a grown-up, technical word either way, not a kitchen word. It has nothing to do with being late for class, even though it looks a bit like late.