blanket mortgage

from The Collaborative International Dictionary of English v.0.48

Blanket mortgage \Blanket mortgage\ or Blanket policy \Blanket
policy\ .
   One that covers a group or class of things or properties
   instead of one or more things mentioned individually, as
   where a mortgage secures various debts as a group, or
   subjects a group or class of different pieces of property to
   one general lien.
   [Webster 1913 Suppl.]