maculation, patch, speckle, dapple, fleck, spot - a small contrasting part of something; "a bald spot"; "a leopard's spots"; "a patch of clouds"; "patches of thin ice"; "a fleck of red"

amyloid plaque, amyloid protein plaque - a plaque consisting of tangles of amyloid protein in nervous tissue (a pathological mark of Alzheimer's disease)

arterial plaque - a fatty deoposit inside an arterial wall; characteristic of atherosclerosis

bacterial plaque, dental plaque - a film of mucus and bacteria deposited on the teeth that encourages the development of dental caries

pathology - the branch of medical science that studies the causes and nature and effects of diseases

monument, memorial - a structure erected to commemorate persons or events