When did we start naming our relatives?

[Dob]

Not even sure we can get a factual answer for this, but I have always wondered at what time in our evolution we decided we needed a name for our mothers brothers, child?

Did names for close relatives come first? Like mom/dad, brother/sister? Followed by Uncle, cousins, etc...?

[Kimstu]

The technical term for this subject is "kinship terminology". This Wiki article has a very brief introduction:

Anthropologist Lewis Henry Morgan (1818–1881) performed the first survey of kinship terminologies in use around the world. Though much of his work is now considered dated, he argued that kinship terminologies reflect different sets of distinctions. For example, most kinship terminologies distinguish between sexes (the difference between a brother and a sister) and between generations (the difference between a child and a parent). Moreover, he argued, kinship terminologies distinguish between relatives by blood and marriage (although recently some anthropologists have argued that many societies define kinship in terms other than "blood").

However, Morgan also observed that different languages (and thus, societies) organize these distinctions differently. He thus proposed to describe kin terms and terminologies as either descriptive or classificatory. "Descriptive" terms refer to only one type of relationship, while "classificatory" terms refer to many types of relationships. Most kinship terminologies include both descriptive and classificatory terms. For example, Western societies provide only one way to express relationship with one's brother (brother = parents' son); thus, in Western society, the word "brother" functions as a descriptive term. But many different ways exist to express relationship with one's male first-cousin (cousin = mother's brother's son, mother's sister's son, father's brother's son, father's sister's son, and so on); thus, in Western society, the word "cousin" operates as a classificatory term.

Morgan discovered that a descriptive term in one society can become a classificatory term in another society. For example, in some societies one would refer to many different people as "mother" (the woman who gave birth to oneself, as well as her sister and husband's sister, and also one's father's sister). Moreover, some societies do not lump together relatives that the West classifies together. For example, some languages have no one word equivalent to "cousin", because different terms refer to mother's sister's children and to father's sister's children.