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

Whisk in pudding mix until starting to thicken, 1 to 2 minutes. — Erin Merhar, Southern Living, 2 Aug. 2026

Cook over low heat for another 5 to 8 minutes until lightly thickened and silky. — Caron Golden, San Diego Union-Tribune, 29 July 2026

Add tomatoes and 1 cup water; cook until slightly thickened, about 5 minutes. — Martha Stewart, 24 July 2026

The butter will help everything emulsify, thickening the sauce and giving it a beautifully glossy sheen. — Rochelle Bilow, Bon Appetit Magazine, 22 July 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