When you come across objects in a painting or story that stand for a concept, the artist or author is using symbolism to convey ideas.
If a particular object keeps popping up at key points in a story, chances are the author is using symbolism to convey an idea or emotion. In the Aesop fable, The Fox and the Grapes, the grapes symbolize things too difficult for someone to attain or achieve. Sometimes people use symbolism in real life. If the president meets a dignitary in the Oval Office, the symbolism of the location says, "I take you especially seriously."
