In Greek, “planet” is from Latin planetaplanetes, from Ancient Greek πλανήτης (planētēs) variant of πλάνης (planēs, “wanderer, planet”).

When the astronomers of antiquity cast their gaze upon the nights sky above, they noticed certain lights wandering about in eccentric patterns of motion, in contrast to the fixed stars in the background. These lights were thought to be gods wandering about in the heavens and were thus named “planets” and received their respective Greek god names, later translated by the Romans into our modern titles for the planets: Mercury, Venus, Earth, Mars, Saturn, Jupiter (Uranus and Neptune were discovered later).