Home › Words › P › photoallergenphotoallergenphotoallergen · noun — A substance that generates an allergic response in the presence of light.Definition from Wiktionary (CC BY-SA 3.0).Among words judged in Lexicurio's Arena, photoallergen ranks #17,018 of 43,113 for Qualifying.EtymologyFrom photo- + allergen.nounA substance that generates an allergic response in the presence of lightDefinitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.photoallergy 83% match — An allergy that is activated by light. vs photoallergen →photoantigen 76% match — A substance that produces an immune response in the presence of light vs photoallergen →photoallergenic 73% match — Relating to, or functioning as a photoallergen vs photoallergen →photoallergenicity 73% match — The condition of being photoallergenic vs photoallergen →allergen 66% match — A substance which causes an allergic reaction. vs photoallergen →photocarcinogen 64% match — Any substance that becomes a carcinogen on exposure to light. vs photoallergen →photosensitivity 62% match — sensitivity to light, especially a heightened response to light vs photoallergen →photodermatosis 62% match — dermatosis caused by or aggravated by exposure to light vs photoallergen →