Celtic knots are perhaps the most notorious and recognizable artwork in Celtic history. They started appearing in history after about 450 AD; the Celtic knots meaning is sketchy at best, because there is little written history documenting their purpose.
However, repetition of their appearance through history in conjunction with other various human interpretations give us insight, and allow us to infer some basic information relating to the Celtic knots meaning.
The Celtic knot symbol, is also referred to as the mystic knot, or the endless knot. The more esoteric or spiritual meaning of this symbol eludes to beginnings and endings. In viewing these beautiful knots, we cannot see a beginning or and end, and therefore we are reminded of the timeless nature of our spirit. This translation hearkens to our most primal selves as we contemplate the infinite cycles of birth and rebirth in both physical and ethereal realms.
A less spiritual representation is also related to the knots endless nature. Due to it's infinite path, the Celtic knot can represent an uninterrupted life cycle. Some may use this symbol as a charm of sorts – warding against sickness or setbacks that might interfere with an otherwise calm and stable life. In this vein, these knots are used as emblems, which can be found in jewelry, clothing, or home decor. In ancient times, gifts adorned with mystic knots would be given with best wishes of longevity, or luck with new endeavors.