Negro
"Negro" replaced the term "colored" as the more polite term. This was done when the term "black" was more offensive. This use of the word was accepted as normal during the Civil Rights Movement of the 1950s and 1960s. It was accepted even by the people it was used to describe.  One example of this is Martin Luther King, Jr. using the term "negro" when talking about his own race in his 1963 speech "I Have a Dream".