diaper, in architecture, surface decoration, carved or painted, generally composed of square or lozenge shapes but also of other simple figures, each of which contains a flower, a spray of leaves, or some such device. The pattern is repetitive and is usually based on a square grid. It was a common form of sculptural wall enrichment in Gothic art. An example is the 14th-century pulpitum, or choir screen, of Lincoln cathedral, Lincolnshire, England.

In Victorian England, attempts were made to reproduce diaper in brickwork, bricks of different colours being used to form bold patterns like pieces of polychrome cross-stitch work. The architect A.W.N. Pugin so embellished his own house, St. Marie’s Grange, near Salisbury. This vogue was, in fact, a revival of brick diapering in Tudor times.