Source : Webster's Revised Unabridged Dictionary (1913)

Twelve \Twelve\, n.
   1. The number next following eleven; the sum of ten and two,
      or of twice six; twelve units or objects; a dozen.

   2. A symbol representing twelve units, as 12, or xii.

   {The Twelve} (Script.), the twelve apostles. --Matt. xxvi.
      20.