PHOTISM By N., Pam M.S. - April 7, 2013 noun. 1. a false interpretation or hallucination of light. 2. a type of synesthesia wherein light or color sensations take place in reaction to arousal of other senses. PHOTISM: "The photism you saw was not actually present on the screen." Related Psychology Terms PHOTOTROPISM PHONISM PHOSPHENE GNOSTIC FUNCTION TRICHROMATISM VISUAL STIMULATION TETRACHROMATISM PHOTOTAXIS AROUSAL-REDUCTION MECHANISM SATURATION SCALE Cite this page: N., Pam M.S., "PHOTISM," in PsychologyDictionary.org, April 7, 2013, https://psychologydictionary.org/photism/ (accessed June 24, 2019).