1. An atmospheric phenomenon consisting of bands of light caused by charged solar particles following the Earth's magnetic lines of force: An aurora is the most intense of the several luminous atmospheric lights appearing sometimes at night as streamers or bands of light that occur in the upper atmosphere over the middle and high latitudes and seen most often in the Artic and Antarctic regions.

An aurora is thought to be caused by charged particles from the sun entering the earth's magnetic field and stimulating molecules in the atmosphere.
2. When capitalized, it means the goddess of the dawn, or the first light of day: In Roman mythology, Aurora was the goddess of the dawn, however in Greek her name was Eos.