Meaning

1. The holder of a secular office, formally subordinate to, but de facto the power behind the throne of, the caliph.
2. A hereditary ruler in various Muslim states (sultanate), varying from petty principalities (as in Yemen), often vassal of a greater ruler, to independent realms, such as Oman, Brunei, Morocco (until 1956) or an empire such as the Turkish Ottoman Empire.
3. A variant of solitaire, played with two decks of cards.
4. A breed of chicken originating in Turkey, kept primarily in gardens for ornamental reasons. See: sultan (chicken)