Racism is the systematic mistreatment of certain groups of people (often referred to as people of color) on the basis of skin color or other (real or supposed) physical characteristics. This mistreatment is carried out by societal institutions or by people who have been conditioned by the society to act, consciously or unconsciously, in harmful ways toward people of color.
Similarly, classism is systematic mistreatment based on socioeconomic status. This mistreatment includes prejudice, discrimination, disrespect, or neglect of rational needs (food, clothing, shelter, communication, opportunities to learn, etc.)