The architecture of Persia was influenced by Arabian architecture; and the peculiarity of Persian and Arabian architecture is the dome, which is called in Arabic the Gunbad and the Mehrab. Gunbad means dome, and Mehrab means an arch used in windows and doors which is not exactly round, but is formed of three or five parts; in other words, in five half-circles with the top made by two lines going upward and joining in the center.