i Register
In some senses, illume is marked as archaic, figuratively, poetic. Watch for register when choosing this word.
verb
To throw or spread light upon; to make light or bright.
Laſt night of all, / When yond ſame Starre that's Weſtward from the Pole / Had made his courſe t’illume that part of Heauen / Where now it burnes, / Marcellus and my ſelfe, / The Bell then beating one.
How dread the thunder's peal that rolls above ! How bright the flashes that illume the sky !
noun
Illumination.
Till lo! at once broad through the gloom, / The lightnings flash’d their dread illume, / Full on a rock by copse embound, / And tore and whirl’d its ruins round; […]
The abdication of belief / Makes the behavior small – / Better an ignis fatuus / Than no illume at all.