The word 'pendulum' is from Modern Latin pendulum, first used around 1643. It is derived from the Latin adjective pendulus "hanging down". While the name we know is pretty old in the scheme of things, it has been used throughout history for more than 1640 prior to it's introduction into Europe.
It is a simple tool used for communicating and gaining guidance from the spiritual world. This is one of the easiest methods of divination and is much more secure and accurate than an Ouija board. When used for divination the pendulum acts as an antenna that amplifies signals or energy vibrations emanating from a spiritual guide or the Divine energies you've called upon. These vibrations focus their attention on the pendulum and cause it to move in specific directions, giving you answers and guidance to the questions you put to the tool. A pendulum is simply a string or chain, weighted by a pointed crystal or some other form of heavy object called a "bob". In our experience, we've had better results from natural materials, such as crystals, and varying forms of metal, silver, gold and so on.