The Collaborative International Dictionary of English v.0.48:

Arrearage \Ar*rear"age\, n. [F. arr['e]rage, fr. arri[`e]re, OF.
   arere. See Arrear.]
   That which remains unpaid and overdue, after payment of a
   part; arrears.
   [1913 Webster]

         The old arrearages . . . being defrayed. --Howell.
   [1913 Webster] Arrect