When you mop the floor, you're typically using a mop. It's like a broom, but instead of sweeping, you are mopping. Wiping a surface means that you're just taking a towel or a sponge and cleaning the tabletop. You can also use "mop" to refer to a really big mess on a surface. For example, "He mopped up the mess with a towel." But this is less common .. . . unless someone makes a habit of spilling an entire pitcher of liquid on the table.Does that make sense?