Previously means at an earlier time, before now or before the moment being discussed. If your teacher asks what you previously learned about fractions, she wants to know what you studied before today. If a book mentions a previously unknown species of beetle, scientists had never identified it until recently.

The word helps us connect events in time. When a news report says a building previously housed a library, we understand it was a library in the past but isn't anymore. When someone mentions they previously lived in Boston, they're telling us about their life before moving somewhere else.

Previously often appears when we're catching up on information or comparing past and present. “As I mentioned previously...” reminds listeners of something said earlier in a conversation. A sequel might start with “Previously on...” to recap what happened in earlier episodes. The word acts like a signpost pointing backward in time, helping us understand how past events connect to what's happening now.