Yes, It is the sign of the Tetragrammaton , the Name of God, and the 4 relationships of the most Holy Trinity.
YOD, HEH VAV, HEH. The two "Heh' being the spirations from both the Father and the Son ( The Holy Ghost)
Of course it is the sign of our Lord's Cross and probably so much more. It is important to sign ourselves correctly and reverently as we are invoking the greatness of the relationship of the Triune God and the Eternal Sacrifice.