nave (nāv) [key], in general, all that part of a church that extends from the atrium to the altar and is intended exclusively for the laity. In a strictly architectural sense, however, the term indicates only the central aisle, excluding side aisles. The floor plan of a wide central portion with narrower aisles on either side existed in the typical hypostyle hall of Egyptian temples and later in the Roman civic basilicas. From the latter it passed into the churches of the early Middle Ages and gradually to Gothic cathedrals. The nave, in the developed Gothic style, became the main body of the structure. Internally the piers, rising the full height of the nave walls to carry the ribs of the four-part vault or sexpartite vault, divided the walls into a series of bays in which three features, ground floor arcade, triforium, and clerestory, were evident, one above another.