n.

1. 晴朗，风和日丽[U]
   He was always a cool man; nothing could disturb his serenity.

   他总是非常沉着；没有什么东西能打乱他的平静。

2. 平静，沉着[U]
3. （大写）尊贵的阁下（对欧洲某些王室成员的尊称）
4. 宁静
   The residents of this community are proud of its serenity, especially at night.

   这个社区的住户以它的宁静为荣，尤其是在晚上。