Caliph: Leader of Muslim nation
The word ‘khalifah’ in the Arabic language has two meanings: 1. A person who is someone’s deputy or succeeds someone by assuming his position of power and authority. 2. A person vested with power and authority. The word is usally used in one of two contexts: either as in [2:30] to refer to the position that mankind has been given on earth, or to refer to the leader of the Muslims who acts as a successor in this regard to the Prophet (saws).
successor or vicegerent. Specifically, it refers to the Muslim ruler.
Successor; inheritor; custodian; vice-regent (see al-Khulafa-ur-Rashidun).
Khalifah or vicegerent is one who exercises the authority delegated to him by his principal, and does so in the capacity of his deputy and agent. This term has been used in the Quran with reference to man: 'Just think when your Lord said to the angels: Lo! I am about to place a vicegerent on earth...' (2:30). At certain places in the Qur'an, khulafa (pl.) also means (a) people with power to mobilize all that is on earth (27:62); (b) successors or inheritors who will inherit the earth and succeed one after another (24:55; 38:26). In the political history of Islam, khalifa became the title of the successors of the Prophet Muhammad (S.A.W.), notably the first four Rightly-Guided Caliphs known as al-Khulafa al-Rashidun (11-35 A.H., 632-655 C.E.). With the establishment of the Umayyad hereditary rule immediately after this, the institution of the Caliphate changed into monarchy. Yet the rulers called themselves Caliphs. Formally the institution of the Caliphate came to an end in 1924 C.E. when Kamal Ataturk of Turkey arbitrarily declared its abolition.
The Imam or the Muslim leader.
the civil and religious leader of a Muslim state considered to be a representative of Allah on earth; "many radical Muslims believe a Khalifah will unite all Islamic lands and people and subjugate the rest of the world"
The word Khalifah refers to the successor or representative of Prophet Muhammad (S.A.W.) or to one of his successors. This person acts as the head of state for the Muslim Ummah. Another title for the Khalifah (English Caliph) is Amir Al-Mu'mineen which means 'the leaders of the believers'. The immediate Caliphs were Abu Bakr As-Siddiq, Omar Ibn Al-Khattab, Othman Ibn 'Affan, and 'Ali Ibn Abi Talib. These were given the nickname of Al-Khulafa'Ar-Rashidun (The Guided Caliphs). Another use for this word is used for humanity in general. The human being is considered the Khalifah (representative) of Allah on earth according to Allah.
The religious and political head of the state for the Muslims.