A shogun (将軍, shōgun?) listen (literally, "a commander of a force") was one of the (usually) hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents (1203–1333), were the de facto rulers of Japan though they were nominally appointed by the emperor. When Portuguese explorers first came into contact with the Japanese (see Nanban period), they described Japanese conditions in analogy, likening the emperor, with great symbolic authority but little political power, to the Pope, and the shogun to secular European rulers, e.g. the King of Spain. In keeping with the analogy, they even used the term "emperor" in reference to the shogun/regent, e.g. in the case of Toyotomi Hideyoshi, whom missionaries called "Emperor Taicosama" (from Taiko and the honorific sama)
The modern rank of shōgun is equivalent to a generalissimo. Although the original meaning of "shogun" is simply "a general", as a title, it is used as the short form of seii taishōgun (征夷大将軍), the governing individual at various times in the history of Japan, ending when Tokugawa Yoshinobu relinquished the office to the Meiji Emperor in 1867.
A shogun's office or administration is known in English as the "office". In Japanese it was known as bakufu (幕府?) which literally means "tent office", and originally meant "house of the general", and later also suggested a private government. Bakufu could also mean "tent government" and was the way the government was run under a shogun. The tent symbolized the field commander but also denoted that such an office was meant to be temporary. The shogun's officials were as a collective the bakufu, and were those who carried out the actual duties of administration while the Imperial court retained only nominal authority.