A tympanum (pl.: tympana; from Greek and Latin words meaning "drum") is the semi-circular or triangular decorative wall surface over an entrance, door or window, which is bounded by a lintel and an arch. It often contains pedimental sculpture or other imagery or ornaments. Many architectural styles include this element, although it is most commonly associated with Romanesque and Gothic architecture.
Alternatively, the tympanum may hold an inscription, or in modern times, a clock face.