Stereotypes

Stereotype: "A conventional, formulaic, and oversimplified conception, opinion, or image."

Stereotypes can be about religion, gender, size, ethnicity, age, race, sexual orientation, nationality, profession, physical appearance, social class, disability, and so much more.

I think that common stereotypes are about race and religion. (ex. All Asians are smart)

Stereotypes could come from centuries ago and taught by parents. Like a child could have those opinions only because their parents told them that and that's the only perspective that they've seen (ex. heiresses). It can also come from individual opinions too.