The Collaborative International Dictionary of English v.0.48:

Sultan \Sul"tan\, n. [F. sultan (cf. Sp. soldan, It. sultano,
   soldano), Ar. sult[=a]n sultan, dominion. Cf. Soldan.]
   A ruler, or sovereign, of a Mohammedan state; specifically,
   the ruler of the Turks; the Padishah, or Grand Seignior; --
   officially so called.
   [1913 Webster]

   Sultan flower. (Bot.) See Sweet sultan, under Sweet.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sultan
    n 1: the ruler of a Muslim country (especially of the former
         Ottoman Empire) [syn: sultan, grand Turk]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

SULTAN. The title of the Turkish sovereign and other Mahometan princes.



U.S. Gazetteer Places (2000):

Sultan, WA -- U.S. city in Washington
   Population (2000):    3344
   Housing Units (2000): 1291
   Land area (2000):     2.982622 sq. miles (7.724955 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    2.982622 sq. miles (7.724955 sq. km)
   FIPS code:            68260
   Located within:       Washington (WA), FIPS 53
   Location:             47.866435 N, 121.809042 W
   ZIP Codes (1990):     98294
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Sultan, WA
    Sultan