From phosphorus + -escent. It's interesting to note that technically phosphorus is not phosphorescent. Phosphorus is luminescent, it gives off light from a chemical reaction, as opposed to re-emission of absorbed energy (phosphorescence). (Reference: John Emsley, The Shocking History of Phosphorus, ISBN 0-330-39005-8.)
- Having the property of emitting light for a period of time after the source of excitation is taken away, e.g., in electrostatic storage tubes and cathode-ray tubes.
- A phosphorescent substance.