roundel [ˈraʊndəl]

例句:

• The master touches the roundel while he whispers something in an unknown tongue.
  园主在低声轻语着某种不知名的语言时触碰了门环.
  
• Note the abstract version of the London Transport roundel logo in the lower right corner.
  来自WSJ
• Items recovered included an oxygen bottle and parts of the aircraft's wooden frame showing an RAF roundel.
  来自BBC