Diamagnetism Definition:

The circulation of electron density in the presence of an external magnetic field, which produces a local (induced) magnetic field that opposes the external magnetic field.

Diamagnetism Explained:

The substance that contains electrons that have completely paired, making this substance have no attractions to magnetic fields. diamagnetism refers to when a magnetic field is in close proximity and the electric charges within the molecule reacts in an opposite manner to the magnetic field present.