A semicircular or polygonal aisle Usually an ambulatory leads around the east end of the choir; separating the choir from apses or chapels; Aisle round an apse
The ambulatory often contained religious relics Large numbers of people made pilgrimages to visit these pieces in basilicas constructed in Romanesque and Gothic times Ambulatories were rounded in order for pilgrims to move about more smoothly
A semicircular or polygonal aisle  Usually an ambulatory leads around the east end of the choir; separating the choir from apses or chapels; Aisle round an apse
Movable, revocable, subject to change Customarily used in discussing wills to denote the power a testator has to change his or her will at any time so desired
1 A semicircular or polygonal aisle enclosing an apse or a straight-ended sanctuary, which provides passage around the sanctuary; originally used for processional purposes 2 In Gothic church architecture, it usually is a continuation of the side aisles around a chancel or apse, providing space for processions around the sanctuary