Supermoon is an astronomical phenomenon that occurs when a full moon coincides with the moon's closest approach to Earth in its orbit. During a Supermoon, the moon appears larger and brighter in the night sky. It is a beautiful sight to behold and a great opportunity for stargazers and
From Wikipedia
A supermoon is a full moon or a new moon that nearly coincides with perigee—the closest that the Moon comes to the Earth in its orbit—resulting in a slightly larger-than-usual apparent size of the lunar disk as viewed from Earth. The technical name is a perigee syzygy or a full Moon around perigee. Because the term supermoon is astrological in origin, it has no precise astronomical definition.