Celtic tattoo designs can be various. Some of them, for example, can represent Celtic crosses, and some – Celtic knots. Usually such Celtic tattoo designs as Celtic knot are made with the use of the single thread which is known under the name of the life thread. Such Celtic tattoo design means the two ways of personal development – spiritual and earthly. Spiral Celtic tattoo designs are popular as well – such Celtic tattoos usually symbolize the Holy Trinity and the growth of everything.