The tam, the standard headgear of Scots ploughmen, was a shortened form of tam-o’-shanter. This cap was usually made of wool or cloth, and while fitting snugly to the head and around the brow, it was wider than the headband. Its distinctive mark was a pompom or a tassel in the center.
Its name derives from Tam O’Shanter, the hero of a Robert Burns poem (1789). The cap must have been a favorite of the poet, for in cartoons and other renderings, he is frequently seen wearing one.
Burns reportedly wrote the poem while walking along the banks of the River Nith. In the poem Tam O’Shanter had disturbed a witch revel and was pursued by the demon Cutty Sark to the bridge over the River Doon. The demon had to stop because it could not cross running water, but it plucked off the tail of Tam O’Shanter’s mare, Maggie.