Da‘wah or Dawah (Arabic: دعوة‎) usually denotes the preaching of Islam. Da‘wah literally means "issuing a summons" or "making an invitation", being the active participle of a verb meaning variously "to summon" or "to invite" (whose triconsonantal root is د ع ى). A Muslim who practices da‘wah, either as a religious worker or in a volunteer community effort, is called a dā‘ī, plural du‘āt. A dā‘ī is thus a person who invites people to understand Islam through a dialogical process, and may be categorized in some cases as the Islamic equivalent of a missionary, as one who invites people to the faith, to the prayer, or to Islamic life. Da'wah activities can take many forms. Some pursue Islamic studies specifically to perform Da'wah. Mosques and other Islamic centers sometimes spread Da'wah actively, similar to evangelical churches. Others consider being open to the public and answering questions to be Da'wah. Recalling Muslims to the faith and expanding their knowledge can also be considered Da'wah.