plaque Definition

plaque
noun

1. A commemorative inscribed tablet fixed to or set into a wall.
2. A wall ornament made of pottery, etc.
3. dentistry.
A thin layer of food debris, bacteria and calcium salts that forms on the surface of teeth and may cause tooth decay.
4. pathol.
A raised area or patch on a body part or surface as a result of damage or disease.

Etymology: 19c: French, from plaquer to plate, from Dutch placken to patch.