“+ noun
Etymology: phot- + sensitization
1. : the process of photosensitizing
2. : the condition of a cell, tissue, or organism acted upon by a substance (as a dyestuff) that renders it sensitive to a particular region of the spectrum to which it was previously insensitive
3. : the development in light-colored skin of an abnormal capacity to react to sunlight typically by edematous swelling and dermatitis that in grazing animals results from ingestion of toxic substances (as porphyrins) that cause the body to absorb ultraviolet rays to an excessive degree where these are not screened out by skin pigments — compare bighead , fagopyrism , hypericism
4. : a chemical change through the agency of a substance excited by the absorption of radiant energy (as light)