Other forms: illuminated, illuminating, illuminates
To illuminate is to light something up. Illuminate the building, brightly illuminated, illuminate the problem.
The literal sense covers floodlights and candles alike. Figuratively it means making something clear: illuminate the argument, an illuminating remark — and illuminating is high praise for an explanation. An illuminated manuscript is one decorated with gold and colour, which is the oldest English sense of the word. Note illumination; and that the Latin means to shine light into.
1verbilluminateTo light something up.
“Floodlights illuminated the castle walls at night.”
2verbclearTo make something clear.
“Her book illuminates the lives of ordinary women in the Middle Ages.”
illuminate is a lighting or clarifying.
Latin illuminare is in plus lumen, light. Luminous, lucid and lunar come from the same light, and the manuscript sense came first into English.
Latin
illūminātus
Middle English
illuminaten
English, today
illuminate
Built from
From Middle English illuminaten, borrowed from Latin illūminātus, perfect passive participle of illūminō (“lighten, light up, show off”) (see -ate for more), from in + lūminō, from lumen (“light”). Cognate with Old English lȳman (“to glow, shine”). More at leam.
Etymology from Wiktionary, CC BY-SA