perimeter

Compared meaning: the boundary line of an area (noun).

比较义项：分隔或围绕某一区域的边界线（名词）。

• border

  Refers to the line separating two neighboring countries, regions, or plots of land; implies two sides facing each other; typical in political and geographic contexts (cross the border, border dispute).

  指两个相邻国家、地区或地块之间的分界线；暗示分界线两侧各有一方；常用于政治和地理语境（如“越过边境”“边界争端”）。

  Farmers on both sides use the river as the border between their land.

  两岸的农民都把这条河当作他们土地之间的边界。

• perimeter 本词

  Refers to the entire outer boundary line enclosing a single area, often used for security or physical space around a building, camp, or field; no sense of two sides, common in phrases like 'around the perimeter'.

  指围绕单一区域（如建筑物、营地、田地）的整条外部边界线，常用于安保或物理空间语境；不涉及“两侧”的概念，常见搭配如“沿周边巡逻”。

  Security guards patrol the perimeter of the factory every two hours.

  保安每两个小时就沿着工厂的周边巡逻一次。

Border and perimeter both mean a boundary line, but border is the line between two neighboring countries or areas. Perimeter is the whole outer line enclosing one area, such as a building. Border can also mean a decorative edge; that sense is not compared here.

这两个词都表示“边界线”，但border强调两个国家、地区或地块之间的分界线，需要双方共同构成边界；perimeter则指围绕单一区域（如建筑物、营地）的整条外边线，常用于安保、巡逻等语境，不涉及“两侧”的概念。这里不比较border作为“花坛、页面等的镶边”这一义项。