The word "government" means order and command.
In the present terminology, it consists of the aggregate of the organized members and the ruling group that control the affairs of society.
It consists of three powers, viz, legislative, executive and judiciary.
As regard the word "jomhoori" (republic), it was first adopted by the Ottoman Turks from the Arabic world "jomhoor" meaning all the people.
Following the example of the French Republic, the word was use by the Ottoman Republic, and from there to other countries.
In the present sense, the world means a democratic government, not headed by a king where sovereignty is entrusted to the representatives elected by people and deriving their power form the people,s will.
As the nature of Islamic government during the time of occultation, in accordance with reason and clear inference agreed with the purport of this expression, so, that world was chosen.
Is it possible to define the Islamic government in a sentence please?
Yes, It is. The Islamic government means the rule of the just successors of the original Imam and the pious elite of the masses, during the occultation of the Imam.