Tartan sett
The repeating pattern of coloured stripes that defines a particular tartan.
Also: sett, plaid
Tartan is a woollen cloth woven with bands of colour running in both directions, which cross to form squares. The sett is the recipe: the order of colours and the number of threads in each stripe. The same sequence is used lengthwise and crosswise, and where two colours cross they blend into a third. Tartans are tied to Scotland, where many are linked with clans, regions or regiments; most of those links were fixed in the 19th century. In North America the pattern is usually called plaid.