Source : Webster's Revised Unabridged Dictionary (1913)

Counter-paly \Coun"ter-pa`ly\ (-p?`l?), a. [F. contre-pal['e].]
   (Her.)
   Paly, and then divided fesswise, so that each vertical piece
   is cut into two, having the colors used alternately or
   counterchanged. Thus the escutcheon in the illustration may
   also be blazoned paly of six per fess counterchanged argent
   and azure.