When can you buy dip?

Excuse me, I'm a bit new to the world of cryptocurrency investing and I've heard the term 'buying the dip' quite frequently. Could you please explain to me, in simple terms, when exactly is the right time to buy the dip? Is it simply when the price of a cryptocurrency drops suddenly, or is there more to it? Are there any indicators or strategies that one should consider before making such a move? I'd really appreciate your insights on this topic.