Barbara Walker, in The Woman's Dictionary of Symbols and Sacred Objects, best describes the symbol of roundness. "The universe begins with roundness: so say the myths. The great circle, the cosmic egg, the bubble, the spiral, the moon, zero, the wheel of time, the infinite womb; such are the symbols that try to express a human sense of the wholeness of things."
Aura – means golden; the astral body; Roman spirit of Air who could fly up to heaven
Black Sun – solar spirit or heavenly god in a cyclic passage through the underworld; symbol of the Egyptian Amen and Seker, the Persian Ahriman, the Mesopotamian Nergal-Ninib, Saturn, Pluto, Hades, Python, Apollyon, Zeus, Chthonios, Yama, Lucifer, Satan, and Beelzebub; originally symbol of the secret, wiser version of the solar god who knew the underworld as well as the heavens
Circle – symbol of a never-ending cycle; primary feminine sign; early matrifocal villages had round hearths, round houses, round fences; symbol of the protected or sacred space; Hindu symbol of the deity, The One, who is everywhere and nowhere; Gnostic circle of the serpent with its tail in its mouth represents the unbroken circle of the cosmos
Dome – from the Latin domus, a house; Italian duomo meaning house of God; often painted blue to represent the sky
Double Wheel – oriental symbol of infinity, the eternal circle of life on earth within the cosmic circle of existence
Halo – symbol of god-like nature; indicates divinity; from the Greek halos meaning round threshing floor where harvest festivals and dances were held as part of the Eleusinian Mysteries
Mandala – symbolic diagram with radial symmetry; often complicated maps of the cosmos
Medicine wheel – Native American symbol; usually contain 28 spokes; dates back to 2500 BC
Orb – three dimensional depiction of the earth; held in the left hand, symbolized the monarch’s domination of the world; with the addition of a crowning cross during the Christian era, symbol of the church’s dominance of the earth
(continued in Round Motifs Part 2)
Walker, B., The Woman's Dictionary of Symbols and Sacred Objects. New York: Harper Collins Publishers, 1988