The fundamental unit of pre-European Maori society, the hapu is between the whanau and the iwi in size, usually totaling between fifty and one hundred fifty people, all of whom hold some genealogical relationship to one another. A single person may be a member of several hapu at the same time, especially if that person's immediate family features many marriages and remarriages from outside the hapu of their parents.
Historically, intertribal conflicts among the Maori usually were conducted between hapu within the same larger iwi, and even in cases of war between one iwi and another, there were many instances of individual hapu staying out of the conflict that their iwi was waging.
Iron Noder 2016, 26/30