thicken
Americanverb (used with or without object)
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to make or become thick or thicker.
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to make or grow more intense, profound, intricate, or complex.
The plot thickens.
verb
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to make or become thick or thicker
thicken the soup by adding flour
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(intr) to become more involved
the plot thickened
Other Word Forms
- rethicken verb
- thickener noun
- unthicken verb (used with object)
Etymology
Origin of thicken
1375–1425; late Middle English thiknen < Old Norse thykkna. See thick, -en 1
Explanation
To thicken is to become denser or to make something thicker. When you accidentally burn dinner, the smoke in the kitchen thickens. Time to get the fire extinguisher. There are two ways to thicken: to become thick or to make thick. Cooks often use flour or cornstarch to thicken sauces. And when you add flour to your brownie batter, you thicken it. An earlier, now obsolete meaning was "to crowd together." The phrase "the plot thickens" means that a situation is becoming more and more complicated or interesting.
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.
At the same time, M proteins can also cause the blood to thicken and concentrate in urine, both of which can cause renal problems.
From Slate • Mar. 29, 2026
When a solar storm hits Earth, it causes the upper atmosphere to expand and thicken, increasing drag on satellites.
From Science Daily • Jan. 28, 2026
One idea BBC News recently looked at was a plan to pump seawater over the surface of Arctic sea-ice in winter to thicken it, giving the ice a better chance to survive the summer.
From BBC • Sep. 9, 2025
But these latest revelations only thicken the mystery: Who was Joan Didion?
From Los Angeles Times • Apr. 22, 2025
The mist seems to thicken in the canopy above us, like the tree trunks are growing directly into the clouds.
From "The Sea in Winter" by Christine Day
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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.