Astrology can be defined as the study of how events on earth correspond to the positions and movements of astronomical bodies which are the moon, sun, planets and the stars.
Paganism in general is a term for the ancient and modern religions which identify nature as the body of the divine e.g. Taoism is the paganism of China, Hinduism is the Paganism of India, Shinto the paganism of Japan and Santeria, Voudon & Macumba are the paganisms of the African Diaspora; etc
On the other hand symbolism is the applied use of symbols i.e iconic representations that carry particular conventional meanings. Symbolism also refers to a way of choosing representative symbols that are in line with the abstract rather than literal properties, allowing for the broader interpretation of a carried meaning than more literal concept-representations can allow. A religion can be described as a language of concepts related to human spirituality. Symbolism hence is an important aspect of most religions.
Zodiac is one of the oldest conceptual images in human history. It reflects the sun as it figuratively passes through the 12 major constellations over the course of a year. It also reflects the 12 months of the year, the 4 seasons, and the solstices and equinoxes. The term Zodiac relates to the fact that constellations were anthropomorphized, or personified, as figures, or animals.