A square aspect is a major aspect. It occurs when a [planet + planet] or [planet + chart point (house cusp, angle, etc.)], or multiple planets/points create a “square” 90° angle on the chart. Exact squares possess the same modality of sign, and classification of house. An aspect is “exact” when it is right on the exact aspect degree, or with a 0° radius, or orb.
Major aspects are typically considered forming/fading within a 10° radius, or “orb”, for planets and house cusps, and 1-2° for minor aspects and relating to asteroids and fixed stars.
Natal Chart
Squares are considered in the natal chart, as a fixed positioning. An exchange between planets and points that plays out in the personality through our whole life.
Examples are:
n Sun square n Moon
Transits
Squares are also considered in transits, the currently shifting planets around their orbits, and how they meet-up, or aspect/exchange mathematically with our natal planets. Transits activate or amplify our natal aspects.
Examples are:
tr Mars square n Neptune
Resistance Harmonic of 1/4
Squares are considered to be significant in that they create an exchange of conflict or resistance between the planets/points (energy), houses (environment) and signs (expression) involved. Squares indicate some kind of work that needs to be done in order to move past the situation and come out stronger. Squares activate both the house and sign that they are present within. The friction created by squares allow an energy of movement, expression and release of “stuck” energy. Squares can be expressed both high and low, it is up to the individual to make the best use of the square energy. As always, other aspects happening in the chart at any given moment can impact how a square is expressed.