From Wikipedia

British Working Class

A stereotype is a commonly held public belief about specific social groups, or types of individuals. The concepts of "stereotype" and "prejudice" are often confused with many other different meanings. Stereotypes are standardized and simplified conceptions of groups, based on some prior assumptions.

Stereotypes are created based on some idea of abstract familiarity. For example, the same behaviour or trait being repeatedly observed by multiple witnesses over an extended period of time. For a stereotype meme to develop and 'stick' in the popular imagination, a stereotype cannot be completely false, and must have an element of social recognition.

A stereotype can be deemed 'positive', or 'negative'. Concepts of stereotype are rarely invoked in instances of positive stereotypes being held about a group. The moniker 'stereotype' is more likely to be deployed in relation to stereotypes deemed to be negative.