2. Noun. (chemistry) The transfer of a photon from one excited state to another, which then undergoes a reaction ¹
¹ Source: wiktionary.com
Medical Definition of Photosensitization
1. 1. Sensitization of the skin to light, usually due to the action of certain drugs, plants, or other substances; may occur shortly after administration of the drug (phototoxic sensitivity), or may occur only after a latent period of from days to months (photoallergic sensitivity, or photoallergy). Synonym: photodynamic sensitization. (05 Mar 2000)