the english and scots word "tartan" is most likely derived from the french ' meaning "tartar cloth". it has also been suggested that "tartan" may be derived from modern scottish gaelic ', meaning "across". today "tartan" usually refers to coloured patterns, though originally a tartan did not have to be made up of any pattern at all. as late as the 1830s tartan was sometimes described as "plain coloured ... without pattern". patterned cloth from the gaelic-speaking scottish highlands was called ', meaning many colours. over time the meanings of "tartan" and ' were combined to describe certain type of pattern on a certain type of cloth. the pattern of a tartan is called a "sett". the sett is made up of a series of woven threads which cross at right angles.