lighten
1 Americanverb (used without object)
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to become lighter or less dark; brighten.
The sky lightened after the storm.
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to brighten or light up, as the eyes or features.
Her face lightened when she heard the good news.
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to flash as or like lightning (often used impersonally with it as subject).
It thundered and lightened for hours.
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Archaic. to shine, gleam, or be bright.
steel blades lightening in the sun.
verb (used with object)
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to give light to; illuminate.
A full moon lightened the road.
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to brighten (the eyes, features, etc.).
A large smile lightened his face.
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to make lighter or less dark.
Add white to lighten the paint.
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Obsolete. enlighten.
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Obsolete. to flash or emit like lightning (usually followed by out, forth, ordown ).
eyes that lightened forth implacable hatred.
verb (used with object)
verb (used without object)
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to become less severe, stringent, or harsh; ease up.
Border inspections have lightened recently.
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to become less heavy, cumbersome, burdensome, oppressive, etc..
His worries seem to have lightened somewhat.
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to become less gloomy; perk up.
People's spirits usually lighten when spring arrives.
verb
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to become or make light
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(intr) to shine; glow
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(intr) (of lightning) to flash
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(tr) an archaic word for enlighten
verb
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to make or become less heavy
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to make or become less burdensome or oppressive; mitigate
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to make or become more cheerful or lively
Other Word Forms
Etymology
Origin of lighten1
First recorded in 1300–50; Middle English lightnen; see origin at light 1, -en 1
Origin of lighten2
First recorded in 1350–1400; Middle English lightnen; see origin at light 2, -en 1
Explanation
To lighten something is to make it brighter or shine a light on it. You can lighten your dark basement room with plenty of lamps and a coat of white paint. Besides "make lighter or illuminate," another meaning of lighten is "make lighter in weight." So you can lighten your load by taking all the heavy books out of your backpack. Figuratively, "to lighten" is to be more cheerful or relaxed, as in: "She decided to lighten the somber mood in the room by telling a few of her funniest knock-knock jokes."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
A playwright friend emailed him when the production was announced with a simple message: “Bart, lighten up!”
From Los Angeles Times ● Aug. 26, 2026
The former heavyweight champion joked and laughed with Wach during their face-off, playfully attempting to lighten the mood before the pair posed for photographs.
From BBC ● Jul. 23, 2026
A greater national investment in mental health care might even lighten his own load, he conceded.
From Barron's ● Jul. 19, 2026
They may lighten the skull or influence voice resonance, and we can even use their size and variability for forensic identification.
From Science Daily ● Jul. 11, 2026
“We are! God, lighten up, Starr,” she says.
From "The Hate U Give" by Angie Thomas
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.