Racism or racialism is a form of race, especially the belief that one race is superior to another. Racism may be expressed individually and consciously , through explicit thoughts, feelings, or acts, or socially and unconsciously , through institutions that promote inequality between races .
In the 19th century many legitimized racist beliefs and practices through scientific theories about biological differences among races. Today, most scientists have rejected the biological basis of race or the validity of "race" as a scientific concept. Racism, then, becomes discrimination based on alleged race. Racists themselves usually do believe that humans are divided into different races .
There are two main definitions of racism today. One of them states that racism is dicrimination based on alleged race, the other - newer - one states that racism has started to include also discrimination based on religion or culture