Prejudice can exist wherever there is any kind of difference between people.
Prejudice based on gender is called sexism. Both women and men can be victims of this, but it is more common for women to be the victims.
Prejudice based on the national grouping or race a person has is known as racism. Colour prejudice is the most common form of racism, as skin colour is a more obvious sign of the race a person belongs to.
It is possible for racism to occur between people of the same skin colour. Connected to this are prejudices based on ethnicity - cultural heritage, language, traditional dress code, etc.
There are forms of prejudice that combine religion and race and it can be difficult to distinguish between the two elements. Prejudice towards Jews is called anti-Semitism. Prejudice towards Muslims is called Islamophobia. Prejudice towards homosexual people is called homophobia.
When people, young or old, suffer from prejudice because of their age, it is called ageism.
Other main categories of prejudice are concerned with social class, disability, life-style choice, eg travellers, and appearance.