What is the meaning of appreciation?

noun

• Understanding of the nature or meaning or quality or magnitude of something.
  • usage: "he has a good grasp of accounting practices"
  • synonyms: grasp, hold
• Delicate discrimination (especially of aesthetic values. )
  • usage: "arrogance and lack of taste contributed to his rapid success"; "to ask at that particular time was the ultimate in bad taste"
  • synonyms: taste, discernment, perceptiveness
• An expression of gratitude.
  • usage: "he expressed his appreciation in a short note"
• A favorable judgment.
  • usage: "a small token in admiration of your works"
  • synonyms: admiration
• An increase in price or value.
  • usage: "an appreciation of 30% in the value of real estate"