The word "planet" comes from the Greek word πλανήτης (planḗtēs), which means "wanderer." This term was used by the ancient Greeks to describe celestial bodies that appeared to wander against the background of fixed stars in the night sky. The Greek verb πλανάω (planáō), meaning "to wander about" or "to stray," is the root of πλανήτης. Hence, planets were called "wanderers" because of their apparent motion distinct from the fixed stars.
