Whereas paint determines the color your eyes perceive, glazes and other finishes control how you perceive that color.
A glaze is a translucent colored medium that can be applied in a particular way over a properly painted base to achieve depth and character that is not possible with paint alone. Glazes can be ragged, stippled, color-washed, stenciled, and more. Glazes create beautiful patinas, and are an initial step when graining or marbling.