Stereotype is a widely held but fixed and oversimplified image or idea of a particular type of thing or person. It can also be a thought that is adopted about specific types of individuals or certain ways of doing things. These beliefs, opinions, or biases may or may not be true or an accurate reflection of reality. Because of stereotyping you can sometimes miss out on a deeper understanding of an individual that can make them unique. There can also be self stereotyping as well.

Example of cultural stereotypes.

Black Americans - None of them can swim, eat fried chicken and water melon, and we are always extremely late.

Black women - suffer from "angry black woman syndrome", don't like to get their hair wet, and treat men disrespectfully.

Lesbians - All lesbians hate men, pretty women can't be a lesbian, and masculine identified  women want to be men/feminine women are pretending to be lesbians.