Tannin

Etymology

From French "tanin," from "tan" (crushed oak bark once used to tan leather). The name is literal: these are the same compounds that turn raw animal hides into leather, and they grip the mouth much as they grip the hide.

noun · /TAN-in/
A group of plant compounds that create a dry, puckering, slightly bitter grip, prominent in red wine, tea, and dark chocolate.
What it names
The backbone that gives red wine its structure and the astringent bite of over-steeped tea.
Example
This young Cabernet is high in tannin, which is why it feels so dry and grippy now but will soften with age.
Related idea
Tannin is the chief cause of astringent mouthfeel — the compound and the sensation are two sides of the same coin, one the substance and the other the feeling it produces.