from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A luminous appearance, image or subjective perception of a hallucinatory nature.
- n. The color that a synesthete may report seeing in association with a particular letter or number
from the GNU version of the Collaborative International Dictionary of English
- n. A luminous image or appearance of a hallucinatory character.
from The Century Dictionary and Cyclopedia
- n. In psychology, a reproduced sensation of color regularly accompanying the arousal of sensation in certain other sense departments, especially in that of hearing: the commonest form of synæsthesia.
From the stem of Ancient Greek φῶς ("light") + -ism. (Wiktionary)