Polymer composed of macromolecules containing carboxylic anhydride groupings as linkages in the backbone: \[\ce{-CO-O-CO\bond{-}}\]
Example:
Source: PAC, 2009, 81, 1131. (Glossary of class names of polymers based on chemical structure and molecular architecture (IUPAC Recommendations 2009)) on page 1149 [Terms] [Paper]