Diaper, a term applied to certain forms of flat or slightly relieved ornament. Any pattern formed of a floral, leafy, geometric, or other device, repeated over a flat surface, is called diaper or diaper work; but according to some authorities the device should be free from bounding lines forming squares, as a pattern of this nature should rather be called checker or checker work.
In textile fabrics the term appears to have been given at one time to silk fabrics with almost any kind of repeated pattern upon them. It is an older name for figured silk than Damask (q.v.). The Byzantine Greeks called a silk with both pattern and ground of one colour diaspron, and the Latins, following the Greeks, named such a fabric diasper, which by a slight change became the English word diaper. Chaucer refers to 'cloth of gold diapered wele' (see Textile Fabrics, by the Rev. D. Rock, D.D.). Any kind of textile fabric, paper, or leather, with a more or less enriched geometrical pattern is, in a general way, said to be diapered. But as regards textiles the term diaper nowadays is almost confined to undyed linen with a woven diamond pattern, although cotton imitations are made. According to the size of this pattern the stuff is called bird's-eye, pheasant's-eye, fish-eye, or Russia diaper.
In Architecture, diaper-work, or diapering, is a kind of decoration applied to plane surfaces, and consists of a small repeated pattern either of conventional flowers, leaves, or other devices, carved or painted. The flower, or other object, is generally inclosed by lines, fillets, or slender mouldings, which constitute in themselves a sort of geometrical diapering. When the pattern is carved, it is generally sunk; and when painted, it consists of a darker shade of the same colour as the plane surface, by which the effect of shadow is communicated to it.
The accompanying illustration, from Bloxam's Gothic Architecture, exhibits a very beautiful example of Decorated English diapering. It is taken from Canterbury Cathedral. In Professor Willis's book on this building other examples are given.