There seems to be a few different origins of the "N" word.   The term is taken from the Latin word Niger or the French word Negre' both meaning black.   When used as a noun it means black person.   We can only assume that it was used as a label to refer to the darker skin people of the society.   The first time the word "slave" was recorded in use was in 1680 Virginia.   Initially the term Niger was probably used during the same time to refer to the slaves at the very beginning of the slave trade.   As the term Niger was used, the pronunciation as well as the definition changed.   Dr. David Pilgrim and Dr. Phillip Middleton, Professors at Ferris State University noted in their paper on the origins of the "N" word, that the mispronunciation of the word Niger by Southern Slave Masters probably gave way to the word Nigger.  

At the same time the Slave Masters' feelings of superiority over the Africans they deemed their cattle grew into contempt and thus the "N" word was born.   Birthed from the phonetically misspelling Slave Master and his hate, the "N" word was documented as first being used in 1786.   The term was probably in use way before then.  

The "N" word was used to refer to slaves throughout the 1700's and 1800's.   Previous to this time the label "Moor" was given to men & women of color.   By the early 1900's the word "Black" began to appear in print in reference to African Americans.   The term was rejected by the community because of its negative connotations and in 1906 Booker T Washington endorsed the term "Negro".   The "N" word, once a common label used for African American people official becomes a derogatory racial epithet.

African Americans started using the "N" word to refer to themselves in the 1920's taking the e r off of the end of the word and adding the letter a, "Nigga".   Although in use in the Black community it was still a pejorative and at some point depending on the social circles denoted class difference.

The definition of the "N" word was a lazy person with no self respect, no regard for family, ignorant, stupid, slow moving, did not speak proper English and had childlike qualities.   The caricatures of Black people in the early 1900's encapsulated this definition.   The age of the Harlem Renaissance challenged this idea.   Alain Leroy Locke, the first Black Rhode Scholar, is credited as the founder of the Harlem Renaissance.   He encouraged Artist, Writers, Poets and Musicians to fully express their African pride by aligning with their rich West African History.   This era brought about the "New Negro".

As the late 1960's approached so did a surge of racial pride and the term "Black" was taken on by the African American community as positive.   The Black Power Movement proclaimed "Black is Beautiful".   The followers of this movement called each other "Brother and Sister" denouncing the use of the "N" word.

The euphemism "The N- Word" came into use during the O.J. Simpson trial.   Newspaper reporters started using "The N-word" or "The N-bomb" in their reports so as not to inflame an already tense trial.  

Today the African American community still differs in its use of the word Nigger.   As some use a neo revisionist attitude in an attempt to redefine the word, still others do not use the word in their vocabulary at all.   In 2003, the NAACP successfully influenced Merriam-Webster Lexicographers to change the definition of the word Nigger in the dictionary so that it would no longer mean African Americans.