The square is the n=2 case of the families of n-hypercubes and n-orthoplexes.

In Astrology, a square (abrv. SQr or Squ) is an angle of 90° (1/4 of the 360° ecliptic, or 1/2 of an opposition [180°]). An orb of somewhere between 5° and 10° is usually allowed. As with the trine and the sextile, in the square, it is usually the outer or superior planet that has an effect on the inner or inferior one. Basically, the square's energy is similar to that of a trine but it is intensified to such an extent that the energy is said to be stressful.

In Alchemy, the square is associated with the number 4 and is said to represent the created Universe as opposed to the spiritual dimensions depicted by the circle. A square is a stable, unmoving shape as opposed to the continual motion of the circle.

Temples and holy buildings are often built in the form of a square, solidly designed to align with the four points of a compass. The Ka'aba at Mecca is a fine example.

To speak of someone as being "square" means they are fixed and unchangeable.