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

This ingredient is absolute magic here, adding umami without the need for stock and a touch of silky starch to thicken the pan sauce. — Chris Morocco, Bon Appetit Magazine, 17 July 2026

The conditions — including the air quality and visibility — improved as Friday progressed, but the National Weather Service warned the smoke could thicken overnight and into Saturday, when rain is expected. — Peter Sblendorio, New York Daily News, 17 July 2026

The landscape thickens, and the region opens into a version of the Dominican Republic deeply tied to land and family. — Rafael Peña, Miami Herald, 15 July 2026

Gengras hangs back, letting his synths thicken the air rather than leaping boldly to the front. — Daniel Bromfield, Pitchfork, 15 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