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

Creamy clam chowder with celery is a light, brothy version of the New England classic, using potatoes to thicken the broth a bit. —Holly Riordan, Better Homes & Gardens, 9 Feb. 2026

Stir and set aside to hydrate and thicken. —Virginia Willis, AJC.com, 8 Feb. 2026

Clouds will continue to thicken through early afternoon, but dry travel should remain dry through mid-afternoon. —Steven Sosna, CBS News, 6 Feb. 2026

Turn chops and cook until sauce is slightly thickened and chops register 145 degrees on an instant-read thermometer. —Gretchen McKay, Twin Cities, 5 Feb. 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