What does the word illusion mean?

Usage examples for illusion

  1. It is the distance which causes the illusion. – The Story of the Heavens by Robert Stawell Ball
  2. When I had said this, he was grave and silent for a little while; and then he answered: " It is impossible, I think, after many years to recover any such illusion. – Hills and the Sea by H. Belloc
  3. True art, he insisted, must have a higher aim than to produce an illusion of the actual. – The Life and Works of Friedrich Schiller by Calvin Thomas