The term "real-time" refers to a system or process where actions or responses occur immediately, or within a specified, predictable time frame. In real-time systems, the processing happens "on the fly," meaning there's no significant delay between input and output.
For example, in real-time communication (like video calls), there’s little to no lag between when you speak and when the other person hears it. Similarly, in real-time systems like air traffic control, actions need to be taken quickly and precisely to avoid risks.
So, it’s called “real-time” because it directly correlates with the present moment—events are processed and responded to as they happen, not in the future or with significant delay.