In the August Wilson play "Fences" is there any special meaning to the use of the word nigger by the characters in the play?

Yes there most certainly is. When Troy calls Bono a nigger it has a much different meaning to it than when he calls his son Cory a nigger. Bono is his friend and Troy means it in a joking sort of way. To his son it is more about control; Troy uses it to intimidate.

Hope that helps.