Definition: A highly reactive, poisonous nonmetallic element occurring naturally in phosphates

Definition: Persistent emission of light following exposure to and removal of incident radiation

Definition: The quantum, or bundle of energy, in which light and other forms of electromagnetic radiation are emitted

Definition: Attractive as a subject for photography; Producing or emitting light

Definition: Movement occurring upon exposure to light

Definition: Use by green plants of the energy in sunlight to carry out chemical reactions

Definition: Science of light; optics

Definition: Living or thriving only in the presence of light