thicken

IPA/ˈθɪkən/
KK[θˈɪkən]IPA/ˈθɪkən/

thicken — verb

  • thickenpresent simple I / you / we / they
  • thickenshe / she / it
  • thickenedpast simple
  • thickening-ing form

1. to increase in thickness so that a liquid or soft substance becomes less runny a

1.verbtransitive / intransitiveB1
Definition

to increase in thickness so that a liquid or soft substance becomes less runny and more solid, or to cause this change to happen.

Example

Sari thickened the gravy with a little cornflour.

transitive: thicken [food] with [ingredient]

The fog thickened as the evening went on.

intransitive: fog thickens over time

Common collocations
  • thicken sauce
  • thicken gravy
  • thicken soup
  • thicken with flour
  • thicken with cornflour
  • thicken naturally
  • thicken gradually
  • fog thickens
  • mist thickens
Synonyms
  • coagulate

    more technical; describes blood, milk, or egg protein becoming semi-solid; not used for general cooking or fog

  • set

    used when a liquid becomes firm enough to hold its shape, like jelly or custard; implies a more complete change than thicken

  • condense

    to become denser or more concentrated, often by losing liquid; used for vapour and some liquids

Antonyms
  • thin

    to make or become less thick; e.g. thin the paint with water, thin the sauce with stock

Grammar Patterns

thicken + object + with + ingredient

subject + thickens (intransitive)

let + object + thicken

Usage Note

Common in cooking contexts. When used transitively (thicken something), the ingredient that causes the change is often stated after 'with' — e.g. thicken the soup with cream, thicken the sauce with egg yolks. The intransitive use often appears in instructions: 'let it thicken' or 'cook until it thickens.' Can also describe natural phenomena like fog or mist becoming denser.

Common Mistakes

I thickened the soup' (with no mention of how).
I thickened the soup with flour.
In recipes, it is natural to say which ingredient you used to thicken with.

2. said in the fixed expression 'the plot thickens' when new events make a confusin

2.verbintransitiveC1
Definition

said in the fixed expression 'the plot thickens' when new events make a confusing situation even harder to understand or explain. The subject is always 'the plot' and the phrase is almost always used in the present or simple past tense as a fixed expression.

Example

The plot thickened when the detective found a second set of fingerprints at the scene.

fixed phrase: 'the plot thickened' + when-clause giving new information

Just as the committee thought the decision was final, the plot thickened with a new legal challenge.

Common collocations
  • the plot thickens
  • the plot thickened
  • plot thickens when
  • plot thickens as
Synonyms
  • intensify

    more general; describes any situation or feeling becoming stronger, not limited to mystery or complication

  • deepen

    used for mysteries, relationships, or conflicts becoming more significant; similar register but not a fixed expression

Antonyms
  • simplify

    to make a situation less complicated or easier to understand

Grammar Patterns

the plot thickens

the plot thickened

Usage Note

This is a fixed idiom that always uses 'the plot' as the subject. You cannot say 'the story thickens' or 'the mystery thickens' in standard English. The expression originated in 17th-century theatre criticism and is still used today in both serious news reporting and lighthearted conversation whenever new information makes a situation less clear. The present tense ('the plot thickens') often signals a dramatic or humorous reveal.

Common Mistakes

This situation thickens every day.
The plot thickens every day.
Only 'the plot' can be the subject of this sense in standard English.
Idioms

the plot thickens

idiom

This phrase means that a situation is becoming more complex and harder to figure out.

When the police found the second letter, the plot thickened.

Did you hear that the suspect has an alibi? The plot thickens!