What is the difference between ceramic vs mosaic?

Painting uses colored chemical compounds as a solute in either water or oil (Hence, having water and oil-based paints). When the solvent (i.e. water or oil) dries, the dried color is more or less plastered to the wall in a very thin, uniform sheet. Brushes, rollers, sprayers all come into play with painting.

A mosaic is basically lots of little colored fragments (e.g. glass, ceramic, etc.) fixed to a surface in a meaningful pattern. Think of a tiled bathroom; if colored tiles were arranged as to create a picture or emblem, basically something with significance, the representation would be a mosaic. The fragments composing a mosaic can be attached to the surface in a number of ways with cements, glues, putties, whatever.