plaque 
(pl
k)
KEY NOUN:
- A flat plate, slab, or disk that is ornamented or engraved for mounting, as on a wall for decoration or on a monument for information.
- A small pin or brooch worn as an ornament or a badge of membership.
- Pathology A small disk-shaped formation or growth; a patch.
- A deposit of fatty material on the inner lining of an arterial wall, characteristic of atherosclerosis.
- A scaly patch formed on the skin by psoriasis.
- A film of mucus and bacteria on a tooth surface.
- A clear, often round patch of lysed cells in an otherwise opaque layer of a bacteria or cell culture.
ETYMOLOGY:French, from Old French,
metal plate, perhaps from Middle Dutch
placke,
disk, patch
