A BBEY In the strict sense, a monastery run by an abbot. Widespread in the Romanesque period, its characteristic architectural features include a church with a larger apse than usual, to accomodate the numerous officiating monks; a large hall (called a chapter house) for the monks’ meetings, and one or more cloisters. ALTARPIECE A painting or, less often, a sculp­ ture in low relief, placed over the altar. It som e­ times consists of several panels when it is called a polyptych; paintings on two panels are known as diptychs, those on three, triptychs. A M B U L A T O R Y A continuation o f the aisles around the choir (see chevet). APSE A semicircular or polygonal projection at the east end of the church, benind the main altar. Semicircular, square or polygonal in form, some churches have three, five or more apses. In these cases the central apse is nearly always larger than the others. Some churches have the apse along the two short sides, a characteristic feature of German Romanesque. Sometimes as well as that at the east end of the church, there are apses on the end walls of the transepts. If the east end and transept apses are the same size it is called a triconch apse. A R C H A curved architectural structure created using stone or brick voussoirs. The arch may be in a wall or supported by columns or piers. The main characteristic is that it transmits its own weight and that of the structure supported in a downward curve and therefore tends to push its supports out­ ward; this must be countered in some way - by adding another arch, creating thrust in the opposite direction (bu ttress), or connecting the low est courses of the arch with an iron chain. The arch can be round, pointed (typical of Gothic), segmental or elliptical - the latter two much used in Baroque art.