Main Entry: plaque

Pronunciation: \ˈplak\

Function: noun

Etymology: French, from Middle French, metal sheet, from plaquer to plate, from Middle Dutch placken to piece, patch; akin to Middle Dutch placke piece, Middle High German placke patch

Date: 1845

1 a : an ornamental brooch; especially : the badge of an honorary order b : a flat thin piece (as of metal) used for decoration c : a commemorative or identifying inscribed tablet
2 a : a localized abnormal patch on a body part or surface b : a sticky usually colorless film on teeth that is formed by and harbors bacteria c : an atherosclerotic lesion d : 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
3 : a clear area in a bacterial culture produced by viral destruction of cells