thicken
UK: ˈθɪkən | US: ˈθɪkən
vt. to make or become thick or thicker
vi. to become more dense or viscous
The word "thicken" combines the adjective "thick" (from Old English þicce, meaning dense or viscous) with the verb-forming suffix "-en," which originates from Old English -nian. This suffix was used to create verbs meaning "to make or become [X]." Over time, "-en" became a productive suffix in English for deriving verbs from adjectives (e.g., "soften," "darken"). The logic is straightforward: "thicken" literally means "to make thick" or "to become thick," reflecting its modern usage in describing increased density or viscosity.
Stir the sauce continuously to prevent it from thickening too quickly.
The fog began to thicken as night fell.
Add cornstarch to thicken the soup.
Over time, the plot of the novel thickens with new twists.
The crowd started to thicken near the entrance.