The space between two supports (wall or pillars) in the longitudinal direction of the naveThe rear part of the church which is reserved for the congregation. The nave extends to the transept., transeptThe transept forms, as it were, the crossbeam of the cruciform floor plan. The transept consists of two semi transepts, each of which protrudes from the nave on the left and right., choirIn a church with a cruciform floor plan, the part of the church that lies on the side of the nave opposite to the transept. The main altar is in the choir., or aisleLengthwise the nave [in exceptional cases also the transept] of the church is divided into aisles. An aisle is the space between two series of pillars or between a series of pillars and the outer wall. Each aisle is divided into bays..