Important definitions to learn...
There are a few definitions that are important to remember when working with magnets.
A magnetic field is the region in which magnetic forces can act. In other words, if you put something magnetic, like iron, near a magnet, but far enough away so that the iron isn't in the magnetic field, the magnet won't attract or repel it.
A magnetic domain is a region in which the magnetic fields of individual atoms are lined up together. In other words, it's a magnetized object, with its atoms all lined up in the same direction.