Definition: A stereotype is a rigid, oversimplified, often exaggerated belief that is applied both to an entire social category of people and to each individual within it. Stereotypes form the basis for prejudice, which in turn is used to justify discrimination and attitudes. They can be positive as well as negative.
Second, break it down to how it relates to literature, to Borges and "The a library of Babel" : A categorization, or a point of reference. This typology of one, radiating out to in an infinite, multi-dimensional space, is that of social necessity. Derived out of fear of not knowing, we establish a datum of reference, a Stereotype, a file cabinet that never ends. Each person person has a folder, a space within the cabinet. It occupies and aggregates with others. It creates tension and harmony.