DuckCorp Dico

Found one definition

1.                 From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
                   
   
   
                   
                     
   seat shells /sˈiːt ʃˈɛlz/
   Sitzschalen <pl>
      Synonyms: seats, seat pans
    see: seat, seat shell, seat pan