The social units that constituted Arabian society in pre-Islamic and early Islamic times (see pre-islamic arabia and the qurʾān ). As the Muslim polity developed, Muslim society became more complex and ¶ tribes ceased to be the sole constituent element. Nonetheless, Arab tribes did not disappear altogether (see arabs; bedouin). Modern historians of Islam understand the word “tribe” as a social unit larger than a “clan,” but there is no consensus about the definition of either of these terms. Other words are occasionally used as synonyms of “clan,” such as “sub-tribe,” “branch,” …