Giant Planet	A massive planet. They are most commonly composed primarily of 'gas' (hydrogen and helium) or 'ices' (volatiles such as water, methane, and ammonia), but may also be composed primarily of rock. Regardless of their bulk compositions, giant planets normally have thick atmospheres of hydrogen and helium.
Mesoplanet	Mesoplanets are planetary bodies with sizes smaller than Mercury but larger than Ceres. The term was coined by Isaac Asimov. Assuming "size" is defined by linear dimension (or by volume), mesoplanets should be approximately 1,000 km to 5,000 km in diameter.
Mini Neptune	A mini-Neptune (sometimes known as a gas dwarf or transitional planet) is a planet smaller than Uranus and Neptune, up to 10 Earth masses. Those planets have thick hydrogen-helium atmospheres, probably with deep layers of ice, rock or liquid oceans (made of water, ammonia, a mixture of both, or heavier volatiles).
Planemo	Planetary-mass object, an object which is hydrostatically round due to self-gravitation, but whose mass is insufficient to initiate fusion at its core to become a star.
Planetar	Either a brown dwarf-an object with a size larger than a planet but smaller than a star—that has formed by processes that typically yield planets; or a sub-brown dwarf, -an object smaller than a brown dwarf that does not orbit a star.
Super Earth	A super-Earth is an extrasolar planet with a mass higher than Earth's, but substantially below the mass of the Solar System's smaller gas giants Uranus and Neptune, which are 13 and 17 Earth masses respectively.
Super Jupiter	A super-Jupiter is an astronomical object that's more massive than the planet Jupiter.
Sub-Earth	Sub-Earth is a classification of planets "substantially less massive" than Earth and Venus.