lighten

1. (transitive) To make brighter or clearer; to illuminate.Examples: "to lighten an apartment with lamps or gas; to lighten the streets"; "A Key of fire ran all along the shore, And lighten’d all the river with the blaze:"Synonyms: light uptransitive

2. (intransitive) To become brighter or clearer; to brighten.intransitive

3. (intransitive, now rare) To flash lightning, to give off lightning.Examples: "Enter the Conjurer; it lightens and thunders […]"; "[…] this dreadful night, That thunders, lightens, opens graves, and roars As doth the lion."; "While we were in the Twins it began to thunder and lighten and pour with rain."archaicintransitive

4. (transitive) To emit or disclose in, or as if in, lightning; to flash out, like lightning.Examples: "[…] behold his eye, As bright as is the eagle’s, lightens forth Controlling majesty:"transitive

5. (archaic) To illuminate with knowledge.Examples: "O Light which mak’st the Light, which makes the Day, Which setst the Eye without and Mind within, Lighten my spirit with one cleare heavenly ray, Which now to view it selfe doth first begin."Synonyms: enlightenarchaic