Zodiac is an imaginary belt in the heavens. The word comes from Greek for circle of the mythological signs, sign of the animal, the Greek word was the ancestor of English zoology, and related terms. The best way to think about the word zodiac, is to think of a circle of little animals.
Each week, by using the Generate Random Letters app./website, a new word will be selected and its history will be described for you.
Miriam Webster New Book of Word Histories