The Tau Cross is so named because it resembles the Greek letter "Tau." Other names for the Tau Cross include the Advent Cross, Anticipatory Cross, Pre-Christian Cross, Old Testament Cross or St. Anthony's Cross.

Other cultures have made use of the shape of the Tau Cross. The Egyptian ankh looks like a Tau Cross topped by a loop. The ankh was also called the Cross of Horus and Key of Life. The Phoenicians adapted the shape to form a crude representation of their goddess Astarte.

Some speculate that the cross might have been especially meaningful to early Christians because it reminded them of the shape that may have resulted when the Israelites painted their doorposts with blood to escape the death of their first-born (Exodus 12:22). Others suggest that the pole Moses placed the bronze serpent upon so that people who had been bitten by snakes might recover was in the shape of the Tau Cross (Numbers 21:8). Still others have suggested that early Christians used the Tau Cross rather than more obvious cross symbols to avoid persecution.

Although the derivation of the Tau Cross is uncertain, it along with the Greek and Latin crosses has provided a basic building block in the development of other cross symbols.