What is the meaning of shading?

noun

• Graded markings that indicate light or shaded areas in a drawing or painting.
• A gradation involving small or imperceptible differences between grades.
  • synonyms: blending

verb

• Cast a shadow over.
  • synonyms: shadow, shade, shade off
• Represent the effect of shade or shadow on.
  • synonyms: shade, fill in
• Protect from light, heat, or view.
  • usage: "Shade your eyes when you step out into the bright sunlight"
  • synonyms: shade
• Vary slightly.
  • usage: "shade the meaning"
  • synonyms: shade
• Pass from one quality such as color to another by a slight degree.
  • usage: "the butterfly wings shade to yellow"
  • synonyms: shade