catflap.org Online Dictionary Query

  square back /skwˈeə bˈak/
  flacher Rücken, gerader Rücken, glatter Rücken
     Synonym: flat back
  
   see: book spine, spine of a book, spine, back of a book, shelf-back, back, backbone, book spines, spines, backs, backbones, cracked spine, tight back, hollow back, loose back, open back, false back, spring back, hand-bound book with French joints