IPA: /ˈθɪkənər/
KK: /ˈθɪkənər/
A substance that is added to a liquid or mixture to make it thicker.
The chef used a thickener to improve the texture of the sauce.
Thickener → It is formed from "thick" (from Old English *þicce*, meaning having a large distance between opposite sides) and "-ener" (a suffix used to indicate a person or thing that performs a specific action). A thickener is something that makes a substance thicker or denser.
Think of something that makes a substance 'thicker' — that's what a thickener does.