Ninety degrees, seven degrees of orb
A square is a quarter of the circle. Here the two bodies are ninety degrees apart, and the orb allowed is seven either way, so anything from eighty three to ninety seven degrees registers. In a full lunar month the Moon makes two squares to Venus, one before the conjunction and one after, so the configuration recurs constantly in the sky and appears in charts at ordinary frequency.
Squares fall between signs of the same mode and different element, which is where their reputation comes from. Cardinal squares cardinal, fixed squares fixed. Aries to Cancer, Taurus to Leo. The two signs share a way of operating and disagree about everything else, and that combination of shared method with opposed substance is the mechanical basis for the friction reading.
Wide squares crossing a sign boundary break that rule and should be read more lightly, since the mode agreement that gives the aspect its logic has gone.
What the friction is actually between
The Moon in the tradition is the reflex layer: appetite, habit, the conditions under which you can rest. Venus is the judging layer applied to pleasure: what you rate, who you find attractive, what you are willing to spend on. A square arranges these so that satisfying one tends to cost the other.
Common descriptions include restlessness with comfortable arrangements, a habit of choosing what is stimulating over what is soothing, and difficulty telling affection from reassurance. None of that is a verdict. A square is read as productive precisely because it does not allow the person to sit still with the tension. Where a trine between the same bodies is often wasted through never being tested, a square is tested daily.
The trap in the older literature is treating this as a statement about someone's love life. It is a statement about incompatible criteria, and where that shows up depends entirely on the houses.
Houses, dignity and the shape of the reading
Take the houses first. A Moon in the second squaring a Venus in the fifth turns the aspect into a running argument between security and enjoyment with a price tag attached. Moon in the tenth squaring Venus in the first makes it about presentation, and how much of yourself you are willing to make agreeable in public.
Dignity then decides which end presses harder. Venus in Taurus or Pisces squaring a Moon in Leo behaves differently from a Venus in Virgo squaring a Moon in Sagittarius, because in the first case the Venus end has weight behind it and in the second it does not. The rest of the chart matters as well: a square that also receives a trine from Jupiter is a different proposition from one standing alone.
Speed, orb and reading your own
Because the Moon covers about thirteen degrees a day against Venus at roughly one, the angle between them changes fast, and a birth a few hours earlier or later can move the orb by several degrees. That is one of the reasons a recorded birth time matters for lunar aspects in a way it does not for slower pairs.
Read a square inside three degrees as a real structural feature. Between four and five it is present but competes with everything else in the chart. At six or seven it is a minor note, and worth checking against the rest of the pattern before giving it much weight. Venus retrograde adds a further layer, since a retrograde Venus is conventionally read as revisiting its own standards rather than applying them straightforwardly.
The check above returns the exact separation, the two signs, the houses and whether the aspect was applying or separating at birth.
Questions people ask about this
What is Moon square Venus?
It is the Moon and Venus ninety degrees apart in the birth chart, allowing seven degrees of orb. The tradition reads it as friction between what makes you comfortable and what you find attractive or worth having.
Does a square always mean difficulty?
It means pressure, which is not the same thing. Astrologers describe squares as aspects that force a response rather than aspects that go wrong, and the outcome is treated as depending on the signs, the houses and the rest of the chart.
How does this differ from Moon opposite Venus?
An opposition puts the two bodies face to face across the chart, so both ends are visible at once. A square sets them at right angles, where each tends to interrupt the other without being seen clearly from the other end.
Does Venus retrograde change the reading?
It adds a qualification. A retrograde Venus is read as working over its own criteria rather than applying them directly, so the square is usually described as slower to resolve and more inward, not stronger or weaker.
Why does birth time matter so much here?
The Moon moves roughly thirteen degrees a day. An hour of error shifts it by about half a degree, which can turn a tight square into a wide one and moves the Moon's house as well.
Can this aspect appear twice in a month?
In the sky, yes. The Moon squares Venus once on the way to the conjunction and once on the way to the opposition. A birth chart records only the moment of birth, so only one of them appears in it.