Celtic Cross (Irish: cros Cheilteach, Scots Gaelic: crois Cheilteach, Manx: crosh Cheltiagh, Welsh: croes Geltaidd, Cornish: krows geltek, Breton: kroaz geltek) is the name given to a symbol that combines a cross with a ring surrounding the intersection.
The Celtic Cross is a beautiful expression of Christianity and is popular throughout the Celtic world and far beyond. Here is a picture of a Celtic design I worked on earlier today (as part of my Occupational Therapy!):