Lot of Marriage
The Lot of Marriage is an Arabic part meant to stand in for the matter of marriage itself. Its real problem is that there isn't one of it — the authorities give at least three different formulas, so the point you compute depends entirely on which one you picked.
The fuller picture
Start with the disagreement, because everything else follows from it. Three formulas are in circulation for the same-named lot. The general English form is the ascendant plus the seventh cusp minus Venus. Bonatti gives a men's form, the ascendant plus Venus minus Saturn. A third form, the one this app computes, is the ascendant plus Saturn minus Venus, reversing by sect. Those are not small variations: on one worked chart the three land in the eighth house, the twelfth and the first respectively. A statement like "the Lot of Marriage is afflicted" carries no information until the formula is named.
It gets worse in an instructive way. One modern practitioner prints the lot in two charts four folios apart and uses a different formula each time — the English cusp form for a woman's question, Bonatti's men's form for a man's — and never states either. Both reproduce from the figures' own numbers, one to twelve arcminutes and the other close enough to confirm all three of its printed claims, so this isn't sloppy arithmetic; it's an undeclared switch on the querent's sex. And the pairing isn't even symmetrical, because the women's counterpart of Bonatti's men's form is a fourth point that fits neither chart. If you use this lot, decide your rule in advance and write it down.
What the lot is allowed to do is narrower than the attention it gets. It can be treated as a stand-in for the seventh house, which means its sign, its house and any planet conjunct or aspecting it are all readable — a benefic close by speaks well of the match, a malefic close by speaks of trouble at the material foundation of it. But an Arabic part corroborates a conclusion the house rulers have already reached. In a marriage question the significators are the ruler of the first, the ruler of the seventh and the Moon; the lot agrees with them or it doesn't, and when it doesn't, they win.
One more limit that comes with every part: no aspect runs from the lot. A planet conjoins or aspects the Lot of Marriage, the lot doesn't reach out to the planet, and nothing about the lot applies or separates. In this app the orb allowed for that contact is deliberately tight.
So the honest summary is that this is a supporting witness with a contested address. Compute it if you like the extra testimony, name your formula, and never let it carry a marriage question on its own.
In your chart
iHorary computes a Lot of Marriage on a sect-keyed formula — ascendant plus Saturn minus Venus by day, reversed at night — which is a different point from either of the two forms the worked charts above use, and our reversal key is the chart's sect where theirs is the querent's sex. In relationship questions about getting married, and only there, three rules read it: the lot standing in the seventh, the lot with a benefic inside five degrees, and the lot with a malefic inside five degrees. All three are weighed as supporting evidence and nothing more. The first of them could open a yes on its own until 2026-08-21, which was more weight than the corroborating role the tradition gives a part; it was demoted to context (register C-182) and now matches what this page says a lot is for.
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