A symbol is the use of a concrete object to represent an abstract idea. It is a figure of speech in which a person, object or situation represent something in addition to its literal meaning. A symbol may appear in a work of literature in a number of different ways to suggest different things.
The word symbolism is literature means that an object in writing stands for something else. For example, if there is a dove in the writing it could stand for peace. If there is a black cat, it could mean bad luck.