The symbol ♉ looks very much like the Greek letter α on its side (and vice versa) and most likely has the same origin, that is, an Egyptian hieroglyph of an ox’s head. Juan Eduardo Cirlot provides an alternative (or complimentary) explanation in his Dictionary of Symbols:
the fact that the sign of Taurus corresponds to the number two relates it to the principle of duality composed of the masculine (Viraj, or Yang) and the feminine (Vac, or Yin). There is also a morphological relationship between the bull, on account of its head and horns, and the waxing and waning aspects of the moon, which is further evidence of the bull’s symbolic function of invigoration, at least in the sublunary sphere. The sign of Taurus governs the throat and voice, and is in turn dominated by Venus.More photos related to zodiac and sea glass @ Shutterstock.