"Retrograde" refers to the apparent backward motion of a planet as observed from Earth. This phenomenon occurs due to the relative positions and movements of the planets in our solar system. For example, when Earth overtakes a slower-moving outer planet like Mars, it appears to move backward in the sky for a short period. In astrology, retrograde motion is often associated with disruptions or challenges in the areas ruled by the retrograde planet. For instance, when Mercury is in retrograde, it is commonly believed to affect communication and technology, leading to misunderstandings and technical issues.