Stereotypes are a widely held but fixed and oversimplified image or idea of a particular type of person or thing. Examples of Stereotypes can be:
All Irish people are drunks
All white Americans are obese, lazy, and dim-witted. Homer Simpson of the TV series The Simpsons is the personification of this stereotype.
All librarians are women who are old, wear glasses, tie a high bun, and have a perpetual frown on their face.
All children don't enjoy healthy food.