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

Vanilla bean paste contains the seeds of the vanilla pod mixed with sugar, extract, and thickening agents. —Alana Al-Hatlani, Southern Living, 6 July 2025

The death of the 32-year-old has shuttered the federal criminal prosecution and thickens the cloud of mystery surrounding the May 17 bombing attack at the American Reproductive Centers fertility clinic in Palm Springs, California. —Scott MacFarlane 6, CBS News, 6 July 2025

For example, Bumble and bumble’s thickening shampoo gives exceptional volume, lift, and bounce—setting the stage excellently for Oribe and Briogeo conditioners to add nourishment ahead of a luscious blowout. —Kiana Murden, Vogue, 16 June 2025

The milk thickens and becomes yogurt.10 Yogurt contains probiotics and nutrients. —Amber J. Tresca, Verywell Health, 6 May 2025

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