The symbolism of the cross is complex. Like the Tree of Life, the cross stands for the world axis. Placed in the mystic Centre of the Cosmos, it becomes the bridge for the soul to reach God. The cross affirms the primary relationship between the two worlds of the celestial and the earthly. It also stands for the conjunction of opposites. Hence its significance as a symbol for agony, struggle and martyrdom. When the cross is T-shaped, it emphasizes the near-equilibrium of the opposing principles.
The Egyptian cross is interesting in view of its antiquity. It stands for life or living. Its shape expresses a profound idea: that of the circle of life spreading outwards from the Origin and falling upon the surface. From the macroscopic point of view, it may represent the sun, the sky and the earth. As a microcosmic sign, that is by analogy with man, the circle would represent the human head or reason, the horizontal arm his arms, and the upright his body.
The Christian tradition enriched the tradition of the cross. It became the symbol of the Crucifixion, the Christ, the Savior, the Word, the second element of the Holy Trinity.
The most general significance of the cross is that of the conjunction of opposites: the positive (or the vertical) with the negative (or horizontal), the superior with the inferior, life with death.