Phosphorescence is when something glows with light without becoming hot to the touch, like the glow-in-the-dark stars on your bedroom ceiling.
Special paint that you can see in the dark has the quality of phosphorescence, and in nature there are certain types of plankton that make moonlit water glow with phosphorescence. It's a scientific term that describes what happens when energy is emitted slowly from an object, appearing as light. It comes from the word phosphorus, a chemical element whose Latin meaning is "light-bringing."