Sociologist Georg Simmel suggested that small groups have distinctive interaction patterns that do not exist in larger groups. In a - (a group composed of two members) - the active participation of both members is crucial for the group's survival.

dyad  

Explanation:

In sociology, a dyad group is described as a group that contains only two member or people and is considered as the smallest social group that is being possible so far. However, according to many sociologists, the pair of individuals who are involved in a dyad group is said to be linked through "romantic interest, work, partners in crime, family relations, some other interests, and so on".

As per the question, the statement signifies a dyad group.                            

nigger, that word was originated for white folks   to keep black people under

and when black people use it, they know that's just how they greet each other

and when white folks use it, they know there's a double meaning under