In astrology, a special calculation (attributed to Arabic astrologers) resulting in points on the chart that are believed to be impactful. To determine them you add the positions of two parts of a chart (such as the Ascendant and the Moon) and then subtract a third factor (such as the Sun).
Readers, please enjoy this guest blog post by Sandra Kynes, author of several books, including The Herb Gardener's Essential Guide, Plant Magic, and the new Witches' Encyclopedia of Magical Plants, among many others.
Although a few old books...