The term 'Sunni' originates from the Arabic word 'sunnī', a relational adjective formed from 'Sunnah', which signifies the established customs and practices of the Islamic prophet Muhammad. This core concept of 'tradition' or 'way' is central to the identity of this branch of Islam, which holds the Sunna, as recorded in the Hadith, as a primary source of religious law and guidance alongside the Quran. The designation emerged historically to distinguish the majority community, who accepted the succession of the early caliphs, from other groups. Thus, the modern term encapsulates a theological and historical identity rooted in adherence to prophetic tradition and communal consensus.

The word 'Sunni' is a loanword from Arabic, derived from the phrase 'ahl al-sunnah wa'l-jamāʻah', meaning 'people of the tradition and the community'. It is not productively segmented into smaller, independent morphemes in English.