The Collaborative International Dictionary of English v.0.48:

Six \Six\, a. [AS. six, seox, siex; akin to OFries. sex, D. zes,
   OS. & OHG. sehs, G. sechs, Icel., Sw., & Dan. sex, Goth.
   sa['i]hs, Lith. szeszi, Russ. sheste, Gael. & Ir. se, W.
   chwech, L. sex, Gr. ??, Per. shesh, Skr. shash. [root]304.
   Cf. Hexagon, Hexameter, Samite, Senary, Sextant,
   Sice.]
   One more than five; twice three; as, six yards.
   [1913 Webster]

   Six Nations (Ethnol.), a confederation of North American
      Indians formed by the union of the Tuscaroras and the Five
      Nations.

   Six points circle. (Geom.) See Nine points circle, under
      Nine.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Six Nations
    n 1: a league of Iroquois tribes including originally the
         Mohawk, Oneida, Onondaga, Cayuga and Seneca (the Five
         Nations); after 1722 they were joined by the Tuscarora (the
         Six Nations) [syn: Iroquois League, League of Iroquois,
         Five Nations, Six Nations]