Dyes and pigments are considered colorants, meaning they are substances that impart coloring to a material.
Dyes are soluble coloring material. Dyes are absorbed into the material to which they are applied. Dyes are transparent. While dyes bring about color changes in wood the molecular size of the dye particles is so small that light is able to pass through.
Pigments are insoluble coloring material.
Paint is a mixture of fine particles of coloring material in a solvent. When applied to a material, the pigments form a thin layer on the surface of the material and actually bond with the surface.
Stains are basically very dilute paints made up of pigment, a carrier and a binder.