Racism is a belief that one race is superior to the other or the practice of treating a person or group of people differently on the basis of their race. (noun)
An example of racism is believing that Caucasians are superior to African Americans.
An example of racism is refusing to hire an Indian person for a job.
See racism in Webster's New World College Dictionary
noun
belief in or doctrine asserting racial differences in character, intelligence, etc. and the superiority of one race over another or others: racist doctrine also, typically, seeks to maintain the supposed purity of a race or the races
any program or practice of racial discrimination, segregation, etc., specif., such a program or practice that upholds the political or economic domination of one race over another or others
feelings or actions of hatred and bigotry toward a person or persons because of their race