Square (Astrology)
A square is a 90° angle between two planets, associated with tension, challenge, and growth through friction.
In astrology, a square is one of the major aspects: two planets are approximately 90° apart (within orb). It is often called a "challenging" or "dynamic" aspect because it correlates with internal tension and external obstacles that can drive growth.
Classical sources like Ptolemy's Tetrabiblos treat squares (and oppositions) as "dissonant" compared to trines and sextiles. Modern psychological astrology views squares as engines of development: the friction between the two planetary principles forces integration.
When interpreting a chart, consider the planets involved, their signs (and dignities), and house placement. Squares to the Sun, Moon, or Ascendant ruler often manifest as recurring life themes.