The apparent backward motion of a planet when it appears, as observed from Earth, to reverse its natural direction of travel and move backward in the zodiac.
When a planet reverses its usual direction of travel (west to east) for a few weeks. When the planet is traveling in the reverse direction (east to west) it is said to be retrograding. After a few weeks the planet reverses again and resumes its normal course.
Westward or backward drift of a planet resulting from the forward motion of the earth as it passes the planet.