Porte (n.)

"Ottoman court at Constantinople," c. 1600, from French, in full, la Sublime Porte, literally "the high gate," translation of Arabic al-Bab al-'Ali, "lofty gate," official name of the central office of the Ottoman government (compare Vatican for "the Papacy," White House for "the United States"). Compare also Mikado. The name supposedly is a relic of the ancient custom of holding royal audience in the doorway of a king's palace or tent.