Littler
Part of speech: adjective
Definition: Small in size.
Smaller
Part of speech: adjective
Definition: Not large or big; insignificant; few in number.
Example sentence: Just as the system of the sun, planets and comets is put in motion by the forces of gravity, and its parts persist in their motions, so the smaller systems of bodies also seem to be set in motion by other forces and their particles to be variously moved in relation to each other and, especially, by the electric force.