@Dzyann "Negro" literally just meant "black"; it was the polite term for black people in the US until the.. like 1950's or 1960's?, if Wikipedia's history's right. It's since been retired, not because the word itself was offensive, but because the attitudes towards black people were. By moving away from the word "Negro", they basically declared all of the pre-existing literature about black people to be dated.
It's kind of an interesting piece of history in that it seems to reflect a success social engineering movement, where it seems that attitudes about race were successfully shifted in conjunction with the retirement of the word "negro". Sort of like what corporations do with rebranding efforts, to move away from an old name with historical baggage, only applied at a social level.
