Word Study
photism
CIDE DICTIONARY
photism, n. [Gr. illumination.].
A luminous image or appearance of a hallucinatory character. [Webster 1913 Suppl.]
OXFORD DICTIONARY
photism, n. a hallucinatory sensation or vision of light.
Etymology
Gk photismos f. photizo shine f. phos photos light
For further exploring for "photism" in Webster Dictionary Online