Source : Webster's Revised Unabridged Dictionary (1913)

Back \Back\, a.
   1. Being at the back or in the rear; distant; remote; as, the
      back door; back settlements.

   2. Being in arrear; overdue; as, back rent.

   3. Moving or operating backward; as, back action.

   {Back charges}, charges brought forward after an account has
      been made up.

   {Back filling} (Arch.), the mass of materials used in filling
      up the space between two walls, or between the inner and
      outer faces of a wall, or upon the haunches of an arch or
      vault.

   {Back pressure}. (Steam Engine) See under {Pressure}.

   {Back rest}, a guide attached to the slide rest of a lathe,
      and placed in contact with the work, to steady it in
      turning.

   {Back slang}, a kind of slang in which every word is written
      or pronounced backwards; as, nam for man.

   {Back stairs}, stairs in the back part of a house; private
      stairs. Also used adjectively. See {Back stairs},
      {Backstairs}, and {Backstair}, in the Vocabulary.

   {Back step} (Mil.), the retrograde movement of a man or body
      of men, without changing front.

   {Back stream}, a current running against the main current of
      a stream; an eddy.

   {To take the back track}, to retrace one's steps; to retreat.
      [Colloq.]