We can use the following examples to illustrate this idea:
When, for example, you say something like:
"That person is my friend"
you are recognising that there is some kind of special relationship between you and that person. This relationship is different to the one created when you say something like:
"That person is my brother / sister / father / mother".
Alternatively, when we say:
"This person is my teacher / employer / probation officer"
another type of relationship is identified.
These examples illustrate some further ideas we can briefly note:
Firstly, as human beings we use labels (such as friend, mother, employer and so forth) as a means of identifying our social relationships.
Secondly, the meaning of any label is, for each of us, the starting point for social interaction. In this respect, every label we identify has certain associated characteristics which we use as the basis for both our understanding of a relationship and our choice of action.
For example, if you think about the characteristics you associate with the label "Sociology Teacher" (and how your interpretation of these characteristics affects your behaviour) this should give you some idea about how this works.
Thirdly, how we interpret a label (what it means to us in specific situations) conditions how we behave in relation to the person so labelled. For example, we will behave towards a "friend" in accordance with the characteristics we assign to this particular label. On the other hand, we may not behave towards a "friend" who also has the label "thief" in quite the same sort of way...
Finally, different societies (and groups within a society) have different "rules of association" relating to how we are expected to behave in different situations and relationships. In some groups, for example, it is customary to kiss when you greet a stranger, whereas in other groups it is customary to simply shake hands...