Sahih Bukhari Volume 6, Book 65, Hadith 4713

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَانُ، أَخْبَرَنَا مَنْصُورٌ، عَنْ أَبِي وَائِلٍ، عَنْ عَبْدِ اللَّهِ، قَالَ كُنَّا نَقُولُ لِلْحَىِّ إِذَا كَثُرُوا فِي الْجَاهِلِيَّةِ أَمِرَ بَنُو فُلاَنٍ‏.‏ حَدَّثَنَا الْحُمَيْدِيُّ حَدَّثَنَا سُفْيَانُ وَقَالَ أَمِرَ‏.‏

Narrated By Abdullah : During the Pre-Islamic period of ignorance if any tribe became great in number, we used to say, "Amira the children of so-and-so." Narrated By Al-Humaidi : Sufyan narrated to us something and used the word 'Amira'.