It's a satellite of the planet.
PLANET
A dwarf planet is a body that orbits the sun - is often beyond the orbit of Jupiter and is classified below a planet. An asteroid is a body that orbits the sun within the asteroid belt.
A planet is a body that orbits around a star.
Asteroid Belt
A body in space that orbits a star and is smaller than a planet is called a "dwarf planet." Dwarf planets, such as Pluto and Eris, share characteristics with planets but do not clear their orbits of other debris. They are part of a larger category of celestial objects that also includes asteroids and comets.
The small body of the moon that orbits a planet is called a satellite.
PLANET
It can be a planet.
planet
A heavenly body that orbits a planet is called a moon. Moons can vary in size, shape, and composition, and they play a significant role in stabilizing the rotation of their host planet.
A dwarf planet is a body that orbits the sun - is often beyond the orbit of Jupiter and is classified below a planet. An asteroid is a body that orbits the sun within the asteroid belt.
Asteroid - a small, rocky body that orbits the Sun.
A planet is a body that orbits around a star.
A moon.
MOON
We would call that body a "planet" of the star.
Asteroid Belt