DuckCorp Dico

Found one definition

1.                 From English - German Ding/FreeDict dictionary ver. 1.9-fd1:
                   
   
   
                   
                     
   sidereal /saɪdˈiəɹɪəl/
   siderisch, sideral, Stern … <adj> [astron.]
         "sidereal period of axial rotation"  - siderische Rotationsperiode
      Synonym: of the star