Banu (بنو) is Arabic for "the children of" or "descendants of" and appears before the name of a tribal progenitor.
Due to the Arabic grammar rules, the word can sometimes become "Bani" depending on the context.
Other than tribes, persons can have the words in their name, Fatima bint Hizam was nicknamed Umm Baneen, "mother of many sons".
Paternal lineage was clearly identified in Arab history as a sign of good or bad standing.
For instance, Beni Yénni or Béni Ourtilane are nowadays the administrative names of Algerian districts called At Yenni and Ayt Wartiran by their inhabitants.