Source : Webster's Revised Unabridged Dictionary (1913)

Arrear \Ar*rear"\, adv. [OE. arere, OF. arere, ariere, F.
   arri[`e]re, fr. L. ad + retro backward. See {Rear}.]
   To or in the rear; behind; backwards. [Obs.] --Spenser.

Arrear \Ar*rear"\, n.
   That which is behind in payment, or which remains unpaid,
   though due; esp. a remainder, or balance which remains due
   when some part has been paid; arrearage; -- commonly used in
   the plural, as, arrears of rent, wages, or taxes. --Locke.

         For much I dread due payment by the Greeks Of
         yesterday's arrear.                      --Cowper.

         I have a large arrear of letters to write. --J. D.
                                                  Forbes.

   {In arrear} or {In arrears}, behind; backward; behindhand; in
      debt.