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.
Tagged: tutorial
Intro to Adobe Illustrator’s Gradient Mesh tool
Ever wonder what you could do with that Gradient Mesh tool in Adobe Illustrator? It’s one of the most powerful, and yet underused tools in the program.
Here’s a great little tutorial to get you started: Magical Butterfly’s Mesh Tutorial.
Illustrator Gradient Mesh tutorial
Life In Vector has a great tutorial on using the Gradient Mesh tool in Adobe Illustrator. It’s available on the download page, and is about a 1.3MB PDF file. You can also view some of the fantastic illustrations, like the car above, done completely in Illustrator.