any lesion of the oral mucosa that presents as bright red plaques or macules with a soft and velvety texture and well-demarcated borders, commonly found in the floor of the mouth, buccal vestibule, the tongue, and the soft palate; an adjacent area of leukoplakia may be found along with the erythroplakia; although erythroplakia is much less common than leukoplakia, erythroplakia carries a significantly higher risk containing dysplasia or carcinoma in situ, and of eventually transforming into invasive squamous cell carcinoma (e.g. oral cancer)