The term SSSB (for small solar system body) was devised recently to offer rationality among terms used to classify solar system bodies/objects, i.e., to be used in official identifications. (Official identifications with the body's characteristics, in turn, are useful for identifying observed bodies as some known object or as-yet-unknown.)
SSSBs are solar system bodies (orbiting the Sun, smaller than dwarf planets. This includes all but the largest minor planets (e.g., all but one asteroids) and also all comets. Moons are not included. It is not clear whether it is to include meteoroids.