Generally, the Celtic star is referred to as the Celtic knot, which means the Father, the Son and the Holy Spirit. However, non-Christians have a different understanding, and many believe that the three points represent life, death and rebirth.
The term Celtic star generally refers to a ship or a fleet of ships that bear the name “Celtic Star.” However, the Celtic knot, which also is known as the Triquetra, has taken on several other meanings since its origins. According to About.com, the Pagans, who were offshoots of the original Druids, believed that the Celtic knot represented the natural forces: earth, air and water. Other Pagans believe the Celtic knot is a symbol of the three different aspects of the feminine energy: the mother, crone and maiden. From a more spiritual perspective, however, it also is believed to represent mind, body and spirit.
When the Celtic knot is accompanied by a circle, it is a symbol of eternity, not only in the Christian tradition but in several other belief systems as well. For instance, many Christians believe that the circle represents the eternity of God’s love when it is included with the Triquetra. For non-Christians, however, it generally represents the eternity of all life. The circle does not change the meaning of the Celtic knot; it simply adds more weight to its original meaning.
Since the Celtic knot has been graphically stylized and used in several different spiritual traditions including Christianity and Paganism, the symbol takes on many different meanings. It simply depends on who is using it and for what purpose.