Wiktionary

1. double planet(Noun)

   a planet with a moon large enough to be considered a planet, were the planet not there, having a substantial portion of the system's overall mass.

2. double planet(Noun)

   a pair of planemos in orbit around each other, where the barycenter of their orbits lies outside of both planemos, which in turn is in orbit about a star.

3. double planet(Noun)

   a pair of planemos in orbit around each other, where the barycenter of their orbits lies outside of both planemos.

4. double planet(Noun)

   a planemo with a moon large enough to be considered a planemo, having a substantial portion of the system's overall mass.