Symbols are simply stored objects created or placed in Adobe Illustrator that you can retrieve easily from the Symbol palette. This includes mesh objects, raster images, text, regular and compound paths or groups of objects. (You cannot, however, create a symbol from a linked piece of art or graphs) 
To create a symbol, select the object you want to make a symbol and either drag the object to the Symbols palette or click the New Symbol button in the Symbol palette. Symbols are especially useful for designers who do their layout in Illustrator, as you can store frequently used Logos and text as a symbol for easy retrieval.
