When the Moon has made the last aspect before exiting a sign she is said to be "void
of course" - usually abbreviated VC or V/C. Although it is debatable what qualifies
as the last aspect, the most common system is to only count major (Ptolemy) aspects.
These are conjunction, opposition, square, trine and sextile. This is the system
used by these tables.
How to read the V/C tables:
Void begins: At this time the Moon makes her last aspect in the current sign. She
is considered to be void of course until entering the next sign.
Void ends: At this time the Moon enters the next sign.
Sign: This is the zodiac sign the Moon is entering.