What is the definition or description of: plaque?

Plaque: A. Pathology a small disk-shaped formation or growth; a patch. B. A deposit of fatty material on the inner lining of an arterial wall, characteristic of atherosclerosis. C. A scaly patch formed on the skin by psoriasis. D. A film of mucus and bacteria on a tooth surface. E. A clear, often round patch of lysed cells in an otherwise opaque layer of a bacteria or cell culture. Thefreedictionary.Com.

Skin lesions: A plaque is a broad, raised area on the skin. For example, patients with psoriasis have a lot of scaly plaques on their body, knees and elbows.