In astronomy, Outer Planet most commonly refers to Jupiter, Saturn, Uranus, and Neptune, the four major planets orbiting beyond the asteroid belt. This usage is different from Superior Planet, which means any planet whose orbit lies farther from the Sun than Earth’s and therefore includes Mars as well. In astrological writing, outer planets may sometimes refer specifically to Uranus, Neptune, and Pluto because of their slow movement and association with collective or transpersonal themes. Other astrological sources may include Jupiter and Saturn in the outer-planet category. Because these conventions differ, the surrounding context is important. Pluto is astronomically classified as a Dwarf Planet, although it remains an important astrological chart factor.
AKA / Related Terms:
Outer Solar System Planet
Sometimes associated with Transpersonal Planet or Generational Planet in astrology, but these are not exact synonyms
Not the same as Superior Planet