thicken

verb

thick·​en ˈthi-kən 

thickened; thickening ˈthi-kə-niŋ 

ˈthik-

intransitive verb

1

a

: to become dense

the mist thickened

b

: to become concentrated in numbers, mass, or frequency

2

: to grow blurred or obscure

3

: to grow broader or bulkier

4

: to grow complicated or keen

the plot thickens

transitive verb

1

a

: to make thick, dense, or viscous in consistency

thicken gravy with flour

b

: to make close or compact

2

: to increase the depth or diameter of

3

: to make inarticulate : blur

alcohol thickened his speech

thickener

ˈthi-kə-nər 

ˈthik-

noun

Examples of thicken in a Sentence

I thickened the gravy with flour.

When the mixture thickens, add the remaining ingredients.

The fog thickened when night fell.

Recent Examples on the Web

Cook mixture over medium heat, stirring constantly with a rubber spatula, being sure to scrape the bottom and corners of the pot, until the mixture is steaming and slightly thickened, 5 to 7 minutes. —Erin Merhar, Southern Living, 4 Apr. 2026

As the minutes passed and the throng thickened, a police officer had to repeatedly remind people not to block the crosswalk. —Hannah Jocelyn, New Yorker, 3 Apr. 2026

Cook over low heat, stirring frequently, until creamy and slightly thickened, about 10 to 15 minutes. —Kelly McCarthy, ABC News, 3 Apr. 2026

The cloud ahead of price is bullish (span A above span B) and often thickens as the trend strengthens. —Karl Montevirgen, Encyclopedia Britannica, 2 Apr. 2026

Word History

First Known Use

14th century, in the meaning defined at intransitive sense 1a

Rhymes for thicken

• chicken
• likin
• quicken
• sicken
• stricken
• indican

Kids Definition

thicken

verb

thick·​en ˈthik-ən 

thickened; thickening -(ə-)niŋ 

1

: to make or become thick, dense, or viscous

thicken gravy with flour

2

: to become complicated

the plot thickens

thickener

-(ə-)nər 

noun