Source : Webster's Revised Unabridged Dictionary (1913)

Six \Six\, n.
   1. The number greater by a unit than five; the sum of three
      and three; six units or objects.

   2. A symbol representing six units, as 6, vi., or VI.

   {To be at six and seven} or {at sixes and sevens}, to be in
      disorder. --Bacon. Shak. Swift.