Definition - What does Yantra mean?
Yantra is a mystical diagram used in the Indian religions and philosophy for worship. It is used to help in meditation and for the benefits of its purported occult powers based on Tantric texts and Hindu astrology. It is a type of mandala, which is a spiritual symbol representing the universe.
In classical Sanskrit, the word, yantra, means “instrument,” “apparatus” or “contrivance.” It is derived from the root word, yam, meaning "to support" or "to sustain the essence of an object/concept."
Yogapedia explains Yantra
Yantra refers to any kind of instrument or machine that aids an enterprise, but the meaning has expanded to refer to religious enterprises as well.
Just as mantras balance the body and mind through sound, yantras provide balance visually. They are geometric and include floral designs. The shapes are believed to have a powerful quieting effect on the mind, and so are used in yogic meditation practice. Yantras are often associated with a particular deity and may be worn as a talisman.
Among the shapes used in yantras are squares, triangles, circles and floral patterns, but more complex symbols may be employed, each with significance. A lotus flower symbolizes the chakra energy centers; a bindu (dot) signifies both the point of creation and the infinite cosmos; a triangle denotes extroversion or masculinity with an upward point, and introversion or femininity with a downward point; and a swastika symbolizes luck and prosperity.