plaque

ot noun

1. In the Hornbostel–Sachs classification system: any flat, thin musical instrument. blown plaques  concussion plaques
2. An abnormal accumulation of material in or on an organ of the body, often associated with disease. amyloid plaque  pleural plaque  senile plaque
3. Any flat, thin piece of clay, ivory, metal, etc., used for ornament, or for painting pictures upon, as a dish, plate, slab, etc., hung upon a wall; also, a smaller decoration worn by a person, such as a brooch.
4. A piece of flat metal with writing on it, attached to a building, monument, or other structure to remind people of a person or an event.