An Etymological Dictionary of the German Language/Placken
Placken, m., ‘patch, piece,’ from MidHG. placke, m., ‘spot, place, district’; comp. Du. plak, ‘spot, blot,’ E. dial. platch (variant of patch). From these G. words, the origin of which is obscure (they can scarcely have originated in Lat. plaga), are derived Fr. plaque, placard, &c. Perhaps UpG. bletzen, ‘to patch,’ which has probably lost a guttural before the tz, is also connected with these cognates.