Definition - What does Sri Yantra mean?
Sri yantra is a sacred geometrical design used for rituals in Hindu Tantra worship and as an aid in yogic meditation. The term comes from the Sanskrit, sri, meaning “radiant” or “splendid,” and yantra, meaning "a mystical diagram."
Sri yantra is also called sri chakra, particularly in its two-dimensional form, and navayoni chakra. Sometimes the name, mandala, is used as a synonym for a yantra; however, some sources cite distinctions even though there is no consensus for what those distinctions are.
Yogapedia explains Sri Yantra
Although there are numerous variations of the sri yantra, each is composed of nine interlocking triangles enclosed in a circle with four pointed upward and five pointed downward. The upward triangles represent the masculine energy of Shiva, while the downward-pointing triangles represent the feminine energy of Shakti. A sri yantra can be drawn on a two-dimensional plane or may be in a pyramid or spherical shape. Because of the nine interlocking and overlapping triangles, a total of 43 triangles are formed, all radiating from a single central point, or bindu.
Yogis believe that the sri yantra represents the cosmic sounds of the universe and can connect them to higher consciousness. Some believe that sri yantra was not created but appeared to yogis who had reached the state of bliss known as samadhi.