In ancient times, when people looked up at the sky at night, they noticed that many of the brightest stars were arranged in a certain pattern, or group. These groups are what we call constellations. The name comes from a latin word meaning group of stars.
What is the zodiac?
In every ancient civilization men gave names to these constellations, calling them after gods and heroes, and after animals and familiar objects.
In studying the constellations, early man noticed that they seemed to march in a great procession across the sky. Certain constellations appeared in the spring, travelled across the sky, and then disappeared. There were followed by summer, autumn, and winter constellations.
Within the process, twelve constellations were noticed in particular. The sun and the moon always rose and set within the part of the sky that held these twelve. And so the part of the sky through which the sun, moon, and the planets travelled was named the zodiac, meaning circle of living things. This was because most of the twelve constellations were named for living things.
The zodiac was divided by the ancients into twelve sections, each named after one of the twelve constellations. We know these constellations as Taurus, the bull; aries, the ram; pisces, the fish; aquarius, the water carrier; Capricorn, the goat; Sagittarius, the archer; scorpio, the scorpion; libra, the scales; virgo, the virgin; leo, the lion; cancer, the crab; and Gemini, the twins.
The twelve constellations were called the signs of the zodiac. Every month a different sign of the zodiac appeared on the eastern horizon, and the sun and the moon seemed to rise in this particular sign.
In addition to the twelve constellations of the zodiac, thirty-six other constellations were familiar to peoples of ancient times. These forty-eight are known as the ancient constellations. Later on, forty other constellations were discovered by astronomers, and these became known as the modern constellations.