Arabs (; , ʿarab) are a major panethnic group whose native language is Arabic, comprising the majority of the Arab world. They primarily inhabit Western Asia, North Africa, and parts of the Horn of Africa. Before the spread of Islam, Arab referred to any of the largely nomadic Semitic tribes inhabiting the northern and central Arabian Peninsula. In modern usage Arab refers to a heterogeneous collection of Arabic-speaking peoples in the Middle East and North Africa. The ties that bind Arabs are linguistic, cultural, and political, and to a lesser extent genetic, with Arabized Arabs displaying genetic admixture from the Arabian peninsula as well as indigenous elements. As such, Arab identity is based on one or more of genealogical, linguistic or cultural grounds, although with competing identities often taking a more prominent role, based on considerations including regional, national, clan, kin, sect, and tribe affiliations and relationships. Not all people who could be considered Arab are identify as such. If the Arab panethnicity is regarded as a single population, then it constitutes the world's second largest group of people after the Han Chinese.