Of, pertaining to, or of the nature of illumination.
1885 J. Martineau Types Eth. Th. II. ii. i. 356 When, from the dull sense..the photistic thrill disengages itself as something different from the rest, it will not be denied that this is a perceptive gain, i.e. an accession not only to the creature's sensory store, but to his life-relations with reality.