a poem (1790) by Robert Burns. Tam o' Shanter, a Scottish farmer, gets drunk one night, and when he is riding home he sees three witches (= women with evil magic powers) and they begin to follow him. He rides away as fast as possible and escapes by crossing a bridge over a river that the witches cannot cross. One of the witches pulls off his horse's tail before it crosses the bridge. The hat which Tam wears in many illustrations of the poem, a traditional round Scottish cap made of wool, is now called a tam o' shanter.