PLAQUE

noun Etymology: French, from Middle French, metal sheet, from ~r to plate, from Middle Dutch placken to piece, patch; akin to Middle Dutch placke piece, Middle High German placke patch Date: 1845 1. an ornamental brooch, a flat thin piece (as of metal) used for decoration, a commemorative or identifying inscribed tablet, 2. a localized abnormal patch on a body part or surface, a sticky usually colorless film on teeth that is formed by and harbors bacteria, an atherosclerotic lesion, a histopathologic lesion of brain tissue that is characteristic of Alzheimer's disease and consists of a dense proteinaceous core composed primarily of beta-amyloid that is often surrounded and infiltrated by a cluster of degenerating axons and dendrites, a clear area in a bacterial culture produced by viral destruction of cells