Sunni (n.)youdaoicibaDictYouDict[Sunni 词源字典]
1620s, from Arabic, "adherent of the Sunnah; Muslim who accepts the orthodox tradition as well as the Quran," from Sunna "traditional teachings of Muhammad" (not, like the Quran, committed to writing, but preserved from his lips by his disciples or founded on his actions), literally "way, custom, course, tradition, usage." Related: Sunnite.[Sunni etymology, Sunni origin, 英语词源]