A stereotype is cultural bias created by attributing real or perceived qualities or behaviour to an entire, or assuming them to be true for every individual within that group. It can be directed at an ethnic, racial or national group, or based on gender, sexual orientation or appearance. The term was coined by the journalist Walter Lippman in the 1920s.
Stereotypes about minority ethnic groups, women, members of religious minorities, young people, old people, people with handicaps, disabilities or exceptional characteristics are all still common in everyday life, but in the decades since Lippman coined the term, human rights advocates in many different arenas have become increasingly adept at confronting, challenging and countering stereotyping.
Enduring stereotypes usually contain an element of truth, which is why they are so powerful and able to last for generations. The problem is that that 'grain of truth' is mistaken for the whole truth, leaving out counter instances, and discounting aspects of social or cultural context.
In modern language, we tend to think of stereotyping as negative bias against an ethnic minority. Stereotyping, as a process of social defining, can be either negative or positive. Positive stereotyping is destructive in its own way, as it a) can create false expectation of members of the group and b) fosters prejudice against non-members, as they are assumed to be lacking in the positive quality or qualities.
Prejudice is often based on negative stereotypes, or on fear of the unknown, or prior experience with an individual and transferred to all members of a group.