Magnetic Resonance refers to a phenomenon in which certain materials, when exposed to an external magnetic field and radiofrequency radiation, absorb energy and undergo changes in their magnetic properties. This process is used in various imaging techniques such as Magnetic Resonance Imaging (MRI) for medical diagnosis or Nuclear Magnetic Resonance Spectroscopy (NMR) for chemical analysis. The term "magnetic resonance" specifically refers to the principle of absorbing energy when subjected to a magnetic field, which is why it's often used in relation to imaging techniques that rely on this phenomenon.