What are 'moon signs'?
Typically, one's "Moon Sign" is seen as the second most important element on a birth chart. (the Sun sign is the most important part, and in third place are all the rest of the planets combined.)
Where the Sun sign reflects the overall personality and the outward appearance of the individual, the Moon represents the inner life of the individual. Generally considered a "female" force, The Moon also represents creativity, nurturing, spirituality, and intuition. The Moon is responsible for all things internal and psychological. The Moon in a chart will color how the individual deals with issues internally and emotionally. The Moon is also sometimes associated with moodiness, and psychological disturbances.
The Moon also represents the primal element of water and the influence that it has over the tides, our bodies and our emotional states. If the Moon is predominant in a chart it may indicate advantages as a creative or an artist, due to skillful harnessing of creative, emotional, and intuitive powers.