A serializable object is one that can be converted into a string of characters and recreated by reading that string back. Almost all objects in Mathematica are serializable--expressions, programs, graphics, typeset mathematics, user interface elements, even complete notebooks. That's because all these Mathematica objects are represented in a uniform way by symbolic expressions; and, being represented in a textual form, symbolic expressions are serializable.

Most aspects of Mathematica have been serializable since its introduction in 1988, but the concept has recently become widely acknowledged with serializable Java and C# objects. Because objects are serializable, MathLink can transmit them to other Mathematica processes--the basis of gridMathematica.