Prejudice
Prejudice is the process of "pre-judging" something. In general, it implies coming to a premature judgement about something without having any direct experience or evidence. It can mean a positive or negative attitude, but we usually use the word in a negative sense. These premature judgements are generally based on stereotypes.
Many prejudicial behaviours are picked up at a young age by children copying their parents' way of thinking and speaking, with no malice intended on the child's part. We may not realise where our prejudiced feelings have originated from, and we may hold prejudiced views without questioning them. Prejudices can be hard to recognise in ourselves, and hard to change. However recognising and confronting our prejudices is the first step towards removing them.
Stereotype
A stereotype is a simplified mental picture of an individual or a group of people who share certain characteristic qualities. The word originated in the field of printing where it originally referred to a printing process used to create reproductions. It came to mean generalisations or overgeneralisations about the members of a group, often used in a negative sense.
We are using stereotypes when we categorise people, and assume they are all the same because they belong to a particular group e.g. all women are caring, all men are brave. Clearly these statements are false because people can all be very different from each other regardless of the 'categories' they fall into. Stereotypes are not only harmful in their own right, but they also do damage by encouraging prejudice and discrimination. For example people may hold negative stereotypes about people from particular countries, or particular religions. We can get rid of stereotyped images we have through education and familiarisation. By finding out more about a particular set of people, or getting to know different individuals from a group, we will usually find out that our stereotypes are false. We may even find that we have more in common with someone from a particular group than we have with other members of our own group.
Discrimination
Discrimination is when prejudice is put into action. It involves classifying people into different groups and giving each group unequal treatments, rights and obligations without a rational justification for the different treatment. It generally refers to treating one group of people less well than another on such grounds as their physical appearance, race, gender, religion, caste, ethnic background, nationality, disability, sexual orientation, ability, age or political views.
Many governments have attempted to control discrimination through civil rights legislation, equal opportunity laws and institutionalised policies of affirmative action. However some governments have supported and formalised discrimination. Examples from the past include apartheid in South Africa, institutionalised racial segregation in the USA from the Civil War to the 1960s, and the treatment of Jews in Nazi Germany.