Tartan (Scottish Gaelic: breacan [ˈpɾʲɛxkən]), also known, especially in American English, as plaid (/plæd/), is a patterned cloth consisting of crossing horizontal and vertical bands in multiple colours, forming repeating symmetrical patterns known as setts. Tartan patterns vary in complexity, from simple two-colour designs to intricate motifs with over twenty hues. Originating in woven wool, tartan is most strongly associated with Scotland, where it has been used for centuries in traditional clothing such as the kilt. Specific tartans are linked to Scottish clans, families, or regions, with patterns and colours derived historically from local natural dyes (now supplanted by artificial ones). Tartans also serve institutional roles, including military uniforms and organisational branding.
Tartan became a symbol of Scottish identity, especially from the 17th century onward, despite a ban under the Dress Act 1746 lasting about two generations following the Jacobite rising of 1745. The 19th-century Highland Revival popularized tartan globally by associating it with Highland dress and the Scottish diaspora. Today, tartan is used worldwide in clothing, accessories, and design, transcending its traditional roots. Modern tartans are registered for organisations, individuals, and commemorative purposes, with thousands of designs in the Scottish Register of Tartans.