cognitohazard UK /kɒɡˈni.təʊˌhæ.zəd/US /kɔɡˈni.toʊˌhæ.zəɹd/ noun1 •A sensory signal (such as an image or sound) that directly causes harmful or undesired physiological effects to one who senses or perceives it.The symbol on that piece of paper is a cognitohazard which puts everyone who reads it in a week-long coma. formscognitohazards