To the ancient Celts the Celtic Trinity Knot or triquetra is used often to symbolize and honor the Mother, Maiden and Crone of the neo-pagan triple goddess. An example is the Celtic Sisters Knot.
The three points of the knot symbolizes the three life cycles of a woman in relation to the phases of the moon.
In more recent times, when Christian missionaries arrived it became recognized as a symbol for The Holy Trinity meaning 'The Father, The Son and The Holy Spirit'. In modern times the Trinity knot is now interpreted as theIrish love knot. The trinity knot's interlaced and unbroken lines symbolize spiritual growth, eternal life, and undying love.