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

Reduce the heat to low and cook, stirring occasionally, until the juices have thickened slightly, about 5 minutes. —Demi Lovato, Bon Appetit Magazine, 20 Mar. 2026

Simmer for 8 to 10 minutes, until the mixture thickens, stirring frequently. —Robin Miller, AZCentral.com, 19 Mar. 2026

Add the mixture to the remaining milk in the pan and cook until the mixture thickens and coats the back of a spoon. —Mary Ann Esposito, Boston Herald, 18 Mar. 2026

Coastal areas could see marine layer low clouds return as early as Friday night and thicken on Saturday night. —Clara Harter, Los Angeles Times, 18 Mar. 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