Photogen

Part of speech: noun

Definitions

1. A chemical compound that emits light upon contact with oxygen, historically used in early lighting devices
2. A material capable of producing luminescence when exposed to air, employed in self-illuminating applications
3. A substance that generates visible light through oxidation, formerly utilized in portable lighting systems

Etymology: "Photogen" is a compound built from "photo-", the combining form of Greek "phōs" (light), and "-gen", from Greek "-genēs" meaning "produced by" or "born of," so the literal sense is something that produces or gives rise to light-related effects. The "-gen" element is far more familiar than it first appears: it also sits inside "oxygen," "nitrogen," and "antigen," all of which take the sense of something that generates or yields a particular substance or effect. Because the word is built entirely from these two elements, its meaning follows directly from them: a thing that is produced by, or responds to, light. The combining form "photo-" in this sense became a productive prefix in the nineteenth and twentieth centuries as photography and its related sciences developed, which is why so many modern coinages share it.

Synonyms: photogenic substance