The term "heliocentric" refers to a model of the solar system where the Sun is at the center, and all the planets, including Earth, orbit around it. This concept contrasts with the earlier geocentric model, which placed the Earth at the center of the universe. The heliocentric theory was first proposed by the ancient Greek philosopher Aristarchus and later developed by Nicolaus Copernicus in the 16th century. The heliocentric model revolutionized our understanding of the cosmos and laid the groundwork for modern astronomy. It was further supported by the observations of Galileo Galilei and the laws of planetary motion formulated by Johannes Kepler. This model is fundamental to our current understanding of the solar system and the movement of celestial bodies.