enlighten

Formerly also inlighten, from Middle English enlightenen, inlightnen, a hybrid formed from Middle English inlighten (“to enlighten, illuminate”), from Old English inlīhtan, onlīhtan, enlīhten (“to enlighten, illuminate, give light to, give sight to”) and Middle English lightnen (“to enlighten, illuminate”) (equivalent to light +‎ -en). Cognate with Dutch inlichten (“to enlighten, inform”), Old High German inliuhten (“to enlighten, illuminate”), Gothic 𐌹𐌽𐌻𐌹𐌿𐌷𐍄𐌾𐌰𐌽 (inliuhtjan, “to enlighten, illuminate”). More at inlight, -en.

enlighten (third-person singular simple present enlightens, present participle enlightening, simple past and past participle enlightened)

1. (transitive) To supply with light; to illuminate.

   The sun enlightens the Earth.

2. (transitive) To make something clear to (someone); to give knowledge or understanding to.
   • 30 October 2016 Bernie Evans writing to The Guardian The big issue: where the true blame lies for our dangerous politics of hate

     Rather than focus on true-to-life drama that might have enlightened viewers, the BBC, frightened by Tory politicians’ threats to its very existence, concentrated its dramatic output on inaccurate historical soap operas, that falsified the view of our past.

   • August 27 1904, John Hossack writing in the New York Times, The Mysteries of the People

     As your reviewer showed, the purpose of the translator and publishers is to help along the labor movement by furnishing a lesson from the past to enlighten the movement of to-day.

   • 1844, Charles Dickens, chapter 20, in Martin Chuzzlewit:

     There was a warning sulkiness in the manner of this speech, which admonished Mr Pecksniff that his dear friend was not to be trifled with or fenced off, and that he must either return a straight–forward reply to his question, or plainly give him to understand that he declined to enlighten him upon the subject to which it referred.

• (illuminate): illumine; See also Thesaurus:illuminate
• (give knowledge to): apprise, notify; See also Thesaurus:inform

• (illuminate): endarken