In astrology, a supermoon is a full or new moon that coincides with a close approach by the Moon to the Earth. The Moon’s distance varies each month between approximately 354,000 km (220,000 mi) and 410,000 km (254,000 mi) due to its elliptical orbit around Earth. The sky over New York was clear, so I took this video.

Astrology  means the study (ology) of stars (astro)
Coincide  means to happen at the same time
Elliptical  means egg-shaped