The electromagnetic force comes from something called an electromagnetic field. In physics, a field is how we keep track of things that might change in space and time. It is like a set of labels for every point in space. For instance, the air temperature in a room could be described by a field, where the labels are just numbers saying how hot it is at that point in the room. We could have more complicated labels as well. On a map of wind speeds, the label could be a number saying how strong the wind is and also an arrow saying which way it is blowing. We call this a vector field because each label is a vector - it has a direction (the arrow) and a magnitude (its strength).