Definition - What does Mani mean?
Mani is the name given to prayer wheels that are used primarily by Buddhists in Tibet and Nepal to enhance spiritual practice.
The mani wheel is a cylindrical structure usually made of metal that is mounted on a shaft or pin and can be spun with a slight brush of the hand. Often beautifully decorated, the mani wheel contains a long strip of rolled up paper inscribed with the words of a prayer or mantra, most commonly Om Mani Padme Hum. These words may also be written on the outside of the cylinder. According to the teachings of Tibetan Buddhism, spinning the wheel is as powerful as reciting the mantras.
The earliest record of prayer wheels are from Ladakh in India in around 400 C.E.The word, mani, is a contraction of the Sanskrit, cintamani, and means "jewel," "precious stone" or "bead."
Yogapedia explains Mani
Some believe that mani wheels symbolize an embodiment of the phrase, “the wheel of dharma,” which Buddha set in motion through his teaching. Mani wheels are also believed to traditionally have been used as a way to ensure those who were illiterate and couldn’t read the sutras could still gain the benefits of chanting the sutras.
The instructions for using mani wheels vary according to different traditions, but they generally prescribe spinning the wheel clockwise and focusing the mind on the repetition of the Om Mani Padme Hum mantra, which is thought to increase the benefit of the practice.
The wheel should be turned gently, with a mindful compassion. That said, the turning of prayer wheels is believed to be so powerful that even absent-minded spinning is effective, and some believe that insects that cross the shadow of the prayer wheel will also feel the benefit. The more the wheel spins, the more the yogi is believed to gain wisdom and merit.