Ambulatory, a cloister, gallery, or alley; a sheltered place, straight or circular, for exercise in walking; the aisle that makes the circuit of the apse of a church. The central eastern apse of a church was often encircled by a semicircular aisle, called the ambulatory. Of these ambulatories there are three species: (1) the ambulatory with tangential chapels; (2) the ambulatory without chapels; (8) variants of the above. By far the most common type is that in which the chapels radiate to the north-east, east and south-east. An ambulatory without radiating chapels is so rare in Romanesque work that supposed examples should be regarded as doubtful. Sometimes there is a rectangular ambulatory, as in the Romsey eastern chapel. Ambulatories are constructed either on the inside or outside of a building, or in a public thoroughfare wholly or partially under cover, or entirely open to the sky, and are used only to walk in. The term is sometimes applied to a covered way round a building, such as the space between the columns and cella of a peripteral temple, or around an open space as the cloisters of a monastic church, as the Campo Santo at Pisa, or the atrium of an ancient basilica, e. g. that of St. Ambrose at Milan. The term can be used as an equivalent of either cloister or atrium.
Longfellow, A Cyclopedia of Works of Architecture in Italy, Greece, and the Levant (New York, 1895); Gwint, Hncyclopedia of Architecture (London, 1881); Bond, Gothic Architecture in England (London, 1905). :