Stoneware is a rather broad term for pottery fired at a relatively high temperature. A modern definition is a vitreous or semi-vitreous ceramic made primarily from stoneware clay or non-refractory fire clay. End applications include tableware, decorative ware such as vases.

Stoneware is fired at between about 1,100 °C (2,010 °F) to 1,300 °C (2,370 °F). Historically, reaching such temperatures was a long-lasting challenge, and temperatures somewhat below these were used for a long time.

It was developed independently in different locations around the world, and this after earthenware and before porcelain. Stoneware is not recognised as a category in traditional East Asian terminology, and much Asian stoneware, such as Chinese Ding ware for example, is counted as porcelain by local definitions. Terms such as "porcellaneous" or "near-porcelain" may be used in such cases. Traditional East Asian thinking classifies pottery only into "low-fired" and "high-fired" wares, equating to earthenware and porcelain, without the intermediate European class of stoneware, and the many local types of stoneware were mostly classed as porcelain, though often not white and translucent.

One definition of stoneware is from the Combined Nomenclature of the European Communities, a European industry standard. It states:

Stoneware, which, though dense, impermeable and hard enough to resist scratching by a steel point, differs from porcelain because it is more opaque, and normally only partially vitrified. It may be vitreous or semi-vitreous. It is usually coloured grey or brownish because of impurities in the clay used for its manufacture, and is normally glazed.