What does "gap" mean?

Native speaker’s answer
Rebecca
In this context, "gap" means "empty space" between two different things. You can see that because of the fallen leaf, part of the line has fallen behind the ones ahead of them, creating a wide, empty space between them. This is called a "gap." Ex: I have a gap between my two front teeth. Ex: There's a gap in the traffic up ahead, see if you can drive ahead of the car in front of us.