What does thicken mean?
Thicken means to become thicker, denser, or more viscous, or to cause something to have those qualities. In cooking, it often describes a sauce, soup, or other mixture changing as liquid evaporates, ingredients are added, or heat alters its consistency. The verb can also be used figuratively for things that become more complicated or intense, such as a mystery, a plot, or a dispute. “The plot thickens” is a familiar expression for a situation in which new complications make events harder to understand. Thickening a mixture is generally achieved by adding flour, starch, or another thickening ingredient, though reduction through cooking and the setting of fats or gels can also produce the effect. The word is useful in both literal and figurative contexts and is common in everyday English in Britain and the United States.
verbTo become thicker, denser, or more viscous, or to cause something to become thicker or denser. It can also be used figuratively to describe something becoming more intense, complicated, or difficult.
- To become thicker, denser, or more viscous, especially as a liquid or mixture changes during cooking, cooling, or chemical processes.
- To make something thicker, denser, or more viscous.
- To become more intense, pronounced, complicated, or difficult, especially in a situation, story, or discussion.
"The sauce will thicken as the flour cooks, so add it gradually."
"The cream thickens as it cools, giving the sauce a rich consistency."
"As the investigation progressed, the mystery thickened and the suspects became more numerous."
A soup can thicken, but a plot can too—and that double life makes this word equally suited to the kitchen and the suspense story.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does thicken come from?
The word comes from Old English þiccan, meaning “to make thick” or “to become thick.” It developed through Middle English as thikken and is related to the Germanic root represented by thick, as well as modern forms such as thickness and thicket. The verb has retained both its physical sense and an older figurative sense involving increasing density, complexity, or intensity.
Related word forms
How thicken is actually used
The verb can be transitive when something is made thicker ('thicken the soup') or intransitive when a substance or situation changes on its own ('the soup thickens'). Its figurative use is common in descriptions of plots, mysteries, tensions, and problems.
Easily confused with thicken
A thicket is a dense group of shrubs or small trees, whereas to thicken is to make something thicker or to become thicker.