Webster's Revised Unabridged Dictionary · 1913

Lighten

Lighten (līt"'n) , intransitive verb

[See Light to alight.]

To descend; to light.
O Lord, let thy mercy lighten upon us. — Book of Common Prayer [Eng. Ed.]

Lighten (līt"'n) , intransitive verb

[Old English lightenen. See Light to kindle, illuminate.]

1.
To burst forth or dart, as lightning; to shine with, or like, lightning; to display a flash or flashes of lightning; to flash.
This dreadful night, That thunders, lightens, opens graves, and roars As doth the lion. — Shakespeare
2.
To grow lighter; to become less dark or lowering; to brighten; to clear, as the sky.

Lighten , transitive verb

[See Light to illuminate.]

1.
To make light or clear; to light; to illuminate; as, to lighten an apartment with lamps or gas; to lighten the streets. [In this sense less common than light.]
A key of fire ran all along the shore, And lightened all the river with a blaze. — Dryden
2.
To illuminate with knowledge; to enlighten. [In this sense less common than enlighten.]
Lighten my spirit with one clear heavenly ray. — Sir J. Davies
3.
To emit or disclose in, or as in, lightning; to flash out, like lightning.
His eye... lightens forth Controlling majesty. — Shakespeare
4.
To free from trouble and fill with joy.
They looked unto him, and were lightened. — Bible (KJV) - Psalm xxxiv. 5

Lighten , transitive verb

[See Light not heavy.]

1.
To make lighter, or less heavy; to reduce in weight; to relieve of part of a load or burden; as, to lighten a ship by unloading; to lighten a load or burden.
2.
To make less burdensome or afflictive; to alleviate; as, to lighten the cares of life or the burden of grief.
3.
To cheer; to exhilarate.
Lightens my humor with his merry jests. — Shakespeare