Triple Crescent

The Triple Crescent is a symbol of the triple goddess. The are several triple goddesses in Celtic mythology and include Anu, Danu as well as Brigid each within there own group.
Triple Crescent symbolizes the three aspects of life - Birth, Life and Death. It is also called the triple moon of the goddess representing the maiden, mother and crone. Also the boy, man and matriarch. Both meanings state the three phases of existence and life.
There are several styles of the Triple Crescent symbol, but all symbolize the three aspects of the moon—waxing, waning, and full moon, as well as Goddess, the feminine polarity of the universe.

Triple Goddess

Sometimes called the Triple Moon, this symbol represents the three phases of the moon: waxing, full, and waning.
According to Robert Graves' The White Goddess, it also represents the three phases of womanhood, in the aspects of Maiden, Mother and Crone, each of which symbolises both a separate stage in the female life cycle and a phase of the moon.
This concept represents the feminine part of Wicca's duotheistic theological system, her masculine part is the Horned God.
Many other neopagan belief systems follow Wicca in their use of the figure of the Triple Goddess, and it continues to be an influence on feminism, literature, Jungian psychology and literary criticism.