In addition to being a given name for humans, Aurelia also refers to a specific type of jellyfish. The “Aurelia” genus of jellyfish is a type of moon jellyfish, which refers to the translucent shape of their bodies and their ability to glow at night.
The Aurelia genus of jellyfish is recognized by the jellyfish body being almost entirely transparent, meaning it is difficult to spot them during the day. However, at night, their bioluminescence makes it far easier to see them, and many are mesmerized by their glow (source).