n. Any chemical reaction in which a compound is decomposed after absorbing a photon
The Century Dictionary and Cyclopedia
n. In botany, the movements of protoplasm under the influence of light: distinguished as apostrophe and epistrophe.
Word Usage
"4 ClOOCl + hv -- ClO + ClO so the rate of photolysis, which is proportional to the absorption cross-section, determines how much ClO is available for the cycle."