the world > the universe > planet > primary planet > secondary planet, satellite > [noun] > small (6)
A little moon, a satellite. Obsolete.
Astronomy. A natural satellite orbiting the moon or other satellite. Now rare.
A small moon or satellite.
Astronomy. Any small celestial object that orbits a planet and is not considered to be a moon; esp. any of the small bodies forming a planetary ring…
Astronautics. A very small planetary satellite (rare); a very small man-made space satellite.