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.
(usually as adjective illuminating
) help to clarify or explain:a most illuminating discussion