During the Pre-lslamic period of ignorance if any tribe became great in number, we used to say, "Amira the children of so-and-so." Narrated Al-Humaidi: Sufyan narrated to us something and used the word 'Amira'.
كُنَّا نَقُولُ لِلْحَىِّ إِذَا كَثُرُوا فِي الْجَاهِلِيَّةِ أَمِرَ بَنُو فُلاَنٍ حَدَّثَنَا الْحُمَيْدِيُّ حَدَّثَنَا سُفْيَانُ وَقَالَ أَمِرَ