A braid (also referred to as a plait) is a complex structure or pattern formed by interlacing three or more strands of flexible material such as textile yarns, wire, or hair. Compared with the process of weaving, which usually involves two separate, perpendicular groups of strands (warp and weft), a braid is usually long and narrow, with each component strand functionally equivalent in zigzagging forward through the overlapping mass of the others. The most common braid is a flat, solid, three-stranded structure. More complex braids can be constructed from an arbitrary number of strands to create a wider range of structures. Braids have been made for thousands of years in many different cultures, and for a variety of uses. Traditionally, the materials used in braids have depended on the indigenous plants and animals available in the local area.
When the Industrial Revolution arrived, mechanized braiding equipment was invented to increase production. The braiding technique was used to make robes, with both natural and synthetic fibers, and coaxial cables for radios using copper wire. In more recent times it has been used to create a covering for fuel pipes in jet aircraft and ships, first using glass fibre, then stainless steel and Kevlar. Pipes for domestic plumbing are often covered with stainless steel braid.