what is mean by magnetism

Magnetism refers to physical phenomena arising from the force between magnets, objects that produce fields that attract or repel other objects.

All materials experience magnetism, some more strongly than others. Permanent magnets, made from materials such as iron, experience the strongest effects, known as ferromagnetism. This is the only form of magnetism strong enough to be felt by people.

Then there's paramagnetism, in which certain materials are attracted by a magnetic field, and diamagnetism, in which materials are repelled by a magnetic field. Other, more complex, forms include antiferromagnetism, in which the magnetic properties of atoms or molecules align next to each other; and spin glass behavior, which involve both ferromagnetic and antiferromagnetic interactions.

Some materials are called non-magnetic, because their magnetic effects are so small. Magnetism can also vary depending on temperature and other factors.