What does photochemical mean?
Photochemical is an adjective describing chemical reactions or processes that are caused by light. The term is especially common in chemistry and environmental science, where it distinguishes reactions initiated by photons from reactions driven by heat, electricity, or ordinary chemical contact. Typical examples include photochemical reactions in the atmosphere, photochemical degradation of materials exposed to sunlight, and photochemical processes involved in biological systems. In everyday discussion, the word is specialized and formal rather than conversational, but it is useful because it identifies the specific role of light in a chemical transformation. The related noun photochemistry names the broader field that studies such reactions, while the adverb photochemically is used to describe how an action or condition occurs. Photochemical should not be confused with photographic, which concerns recording images, or photogenic, which means attractive or suitable for photography.
adjectiveRelating to or involving chemical reactions caused by light. In technical contexts, it may also refer to substances or processes whose behavior depends on exposure to light.
- Relating to a chemical reaction or process caused by light.
"The researchers studied the photochemical degradation of plastic exposed to sunlight."
"The photochemical reaction produces a measurable change in the solution."
"Exposure to ultraviolet light accelerated the photochemical breakdown of the coating."
Photochemistry powers everything from camera film to the chemistry of twilight, showing how light can transform matter.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does photochemical come from?
The word was formed in English by combining photo-, a combining form associated with light and ultimately Greek phōs, with chemical, an adjective and noun derived from the tradition of alchemy and chemistry. The compound became established as scientific terminology as researchers increasingly described reactions caused by exposure to light. Its close relatives include photochemistry, the study of light-driven chemical reactions, and photolysis, a chemical process in which light breaks molecules apart.
Related word forms
How photochemical is actually used
A technical term used chiefly in chemistry, environmental science, photobiology, and related fields. It is more specific than simply saying that a chemical process involves light.