A prejudice is a negative or hostile attitude toward a person or group. This attitude is usually formed without sufficient information or is based on limited experiences. Prejudice is a way of thinking and not necessarily an action, although people can act on their prejudice. Like a stereotype, a prejudice is often difficult to change. A prejudice is much more encompassing than a stereotype.
Discrimination is unequal treatment of people based on their membership in a particular group.
Unlike prejudice, which is an attitude, discrimination is a behavior. Racism is the result of racial or cultural prejudices exercised against a group by those in positions of power. Whether intentional or unintentional, racism can be practiced by the economically, socially or politically powerful. There are different types of racism as well, such as institutional racism or biological racism. Like a doctor who must make a proper diagnosis in order to properly treat an illness, people who are tackling issues of discrimination and racism must also properly define these social cancers in order to help find the cure.