http://www.tribal-celtic-tattoo.com/celtic.htm
The great majority of the Celtic designs used in modern tattooing come to us through the illuminated manuscript tradition. These books are visual metaphors of faith, and were carried from Ireland, where they were created, throughout Europe after the Dark Ages by traveling Saints and scholars.
Although most people are seeking for "meaning" in their lives and tattoos, it is nevertheless true that the most delightful knotworks, braids, and zoomorphic animal figures are illustrations used to fill up precious vellum page space around texts from the Bible. It is not necessary to know what they might have "meant" to the monks who painstakingly painted them. If the design speaks to you, it can be your tattoo. By wearing it you will learn meanings.
Celtic and Tribal Tattoos
For people of Celtic heritage, be they Irish, Scots, Manx, Welsh or Breton, these designs can be a way of showing pride in their heritage by reaffirming an affinity with a highest expression of an indigenous artistic style.
http://www.lodelink.com/laura/tatoo/tatoos.html
http://www.celtictattoo.com/
Continued...
will be continued, but I haven't got around to it yet.