Mandalas are works of sacred art in Tantric (Tibetan) Buddhism. The word "mandala" comes from a Sanskrit word that generally means "circle," and mandalas are indeed primarily recognizable by their concentric circles and other geometric figures. Mandalas are far more than geometrical figures, however. For Tantric Buddhists, they are rich with symbolism and sacred meaning. In fact, the etymology of the word "mandala" suggests not just a circle but a "container of essence."
Simply stated, a mandala is a sacred geometric figure that represents the universe. When completed, a mandala becomes a sacred area that serves as a receptacle for deities and a collection point of universal forces. By mentally entering a mandala and proceeding to its center, a person is symbolically guided through the cosmos to the essence of reality. By constructing a mandala, a monk ritually participates in the Buddha's teachings.
