1 [with object] light up:a flash of lightning illuminated the house figurativehis face was illuminated by a smile decorate (a building or structure) with lights for a special occasion.
2 (often as adjective
illuminated)
decorate (a page or initial letter in a manuscript) with gold, silver, or coloured designs.
3 (usually as adjective
illuminating)
help to clarify or explain:a most illuminating discussion