The besom is a broom used in modern Pagan and Wiccan ritual to sweep a space clean before a working, and what it sweeps away is understood to be not dust but the ordinary and the unwanted.
Ritual cleansing
Before a rite the space is symbolically swept with the besom, clearing it of mundane and negative influences so that it is fit for the working, a cleansing that is of the atmosphere of the place rather than its floor. The broom is also stood by a doorway, laid down as a boundary marker, or used in particular ceremonies, and in some traditions a couple jumps the broom together as part of a wedding, a custom drawn from folk practice. Its function is to mark and to purify the threshold between ordinary space and sacred space.
Folk roots and reclaimed image
The besom draws on European folk custom, in which the household broom carried protective and cleansing associations, and on the folkloric image of the witch broom, which the modern traditions have taken up and turned to their own use. Modern Paganism and Wicca, largely shaped in the twentieth century, gathered such inherited objects and gave them a place in a reconstructed ritual practice, so the besom carries both a genuine descent from folk custom and a meaning assigned to it within the modern revival. As with the cauldron, its use in the circle rests on that double inheritance of old association and recent ordering.