A pendulum is a weighted object suspended from a chain or cord, used as a divination tool to answer yes-or-no questions. The person holding it asks a question and interprets the direction or pattern of its swing, a back-and-forth motion often read as "yes," a circular motion as "no," typically after first establishing which direction represents which answer.

Some readers use a pendulum on its own, while others pair it with a chart, mapping letters or answers around its base, to spell out more detailed responses beyond a simple yes or no.