Negro is a term for Black people, up to about 1960 or 1970 it was common and Martin Luther King Jr among others used it. Today the word is used though negro is rarely used in the African American community and negro is usually considered offensive.
This article is needed because because people who aren't Racist but who speak English as a second language may read, negro in writings by Martin Luther King Jr. or similar works from that period. Liberapedia needs to warn such people to be careful how they use the word.
Negro is also the Spanish word for black.
British English uses the word to refer to people with mulatto backgrounds, incidentally the word mulatto can also be offensive and is best avoided.