It is common to hear horary astrologers use the expression void-of-course (VOC) in reference to the Moon when it makes no more aspects before it leaves its present sign.
No more aspects
Some astrologers say that the Moon is VOC if it doesn’t make another aspect for the radius of its orb: 13 degrees, even though it may aspect another planet before leaving its present sign.
A Consideration
A VOC Moon is one of the so-called Considerations used by horary astrologers when judging a chart.
Its general interpretation is that nothing will come of the matter asked about, unless there is strong contradictory evidence presented in the chart.
Not really of course
However the expression void-of-course is actually a misnomer.
In modern English the expression of course suggests something that is obvious, or common knowledge, or similar, and the expression ‘VOC’ seems odd.
Bonatti
However Bonatti (Book on Astronomy, Vol 1, Chapter 10: On the voiding of the course of the planets, page 214′; translated by Ben Dykes) uses the expression ‘in-course’ meaning a planet in the course of its travels through a sign.
Running alone
If it doesn’t aspect another planet before it leaves its present sign it is void-in-course, and runs alone.
An adjustment is required
Changing the expression from void-of-course to void-in-course dispenses with any confusion regarding the modern understanding of the phrase of-course, and makes its meaning more obvious. Using just the word void as in the Moon is void is also a positive step, but not as self-explanatory as in-course. Somewhere between Bonatti and Lilly the expression changed from void-in-course to void-of-course.
Learning astrology can be challenging enough at times without having to learn the meaning of terms which are themselves a corruption that confuses people in contemporary society. If a small adjustment is made, and the term VOC is replaced by the term void-in-course, then fewer people would be confused and astrology move a step closer to broader acceptance.