tran·quil·i·ty /trænˈkwɪləti, træŋ-/
  寧靜
  tranquility
       n 1: a disposition free from stress or emotion [syn: repose, quiet,
             placidity, serenity, tranquillity]
       2: a state of peace and quiet [syn: tranquillity, quietness,
           quietude]