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.
- To supply with light; to illuminate; as, the sun enlightens the earth.
- To make clear to the intellect or conscience; to shed the light of truth and knowledge upon; to furnish with increase of knowledge; to instruct; as, to enlighten the mind or understanding.