Void / void of Course
Void - literally 'empty' of influence. The term is especially applied to the Moon when it is out orb of any aspect, and suggests a lack of impetus to move events in any direction.
Void of course is when a planet remains out of orb of any aspect for the duration of its movement through its sign.
- William Lilly writes:
"A Planet is void of course, when he is separated from a Planet, nor does forthwith, during his being in that Sign, apply to any other: This is most usually in the Moon; in judgments do you carefully observe whether she be void of course yea or no; you shall seldom see a business go handsomely forward when she is so."
The keyword here is 'forthwith', which means "immediately"; "at once"; or "without delay:" So to avoid being void of course the planet has to enter into orb of another aspect either during its separation from its last aspect, or immediately as it becomes fully separated (at that instance).
See also Void of Course: Definitions Old & New.