Definition (Cambridge Dictionary): an area of a country or town that has fixed borders that are used for official purposes, or that has a particular feature that makes it different from surrounding areas（多指由政府等机构出于行政管理等目的而明确划分的地区）

Example:

the business district of New York

纽约的商业区

South Cambridgeshire District Council

剑桥郡南区议会

Definition (Cambridge Dictionary): an area, especially one that is different from the areas around it because it has different characteristics or is used for different purposes（科技用词，指圆形或弧形地带，尤指地图上按温度划分的五个地带。用作一般意义时，也可指具有某种特征的其它地区）

Example:

a nuclear-free zone

无核区

This stretch of coast has been designated a danger zone.

这段海岸已被划定为危险地带。

The UN Security Council has established a no-fly zone.

联合国安全理事会设定了一处禁飞区。