What is distance time graph?

A graph which shows how distance(dependent quantity) varies with time(independent quantity). For example, if you want to know how much distance a hare covers in a running race, you plot time along x axis, in seconds(say), and the distance it has traveled along the y axis, in meters(say) , so that by looking at the graph, you know how much distance the hare has traveled from the starting point at any instant of time, or distance between any two given times, and so on!

Of course, I don't see why it features here in the relativity section! Or is it that you are asking what a space-time diagram is?