名詞 perimeter:

1. the boundary line or the area immediately inside the boundary
   同義詞：margin, border
2. a line enclosing a plane areas
3. the size of something as given by the distance around it
   同義詞：circumference

1. The plane stalled, flipped over onto its back and crashed near the perimeter.
   飛機(jī)失速了，翻了一個(gè)跟頭，墜毀在機(jī)場(chǎng)環(huán)形圍欄附近。
2. Guards had been posted at several points around the perimeter.
   在環(huán)形防線上已布置了幾處崗哨。
3. The barbed wire fence round the perimeter discouraged intruders.
   周圍有鐵絲網(wǎng)阻止了外人闖入。

pe.rim.e.ter

n.（名詞）
Mathematics
【數(shù)學(xué)】
A closed curve bounding a plane area.
周界：圍繞一平面域的封閉性邊界
The length of such a boundary.
周長(zhǎng)：此類邊界的長(zhǎng)度
The outer limits of an area.See Synonyms at circumference
一區(qū)域的外限參見 circumference
A fortified strip or boundary usually protecting a military position.
周界：筑有防御工事的地帶或邊界，常用以保護(hù)一軍事地點(diǎn)

來源：
Middle English perimetre
中古英語(yǔ) perimetre
from Latin perimetros
源自 拉丁語(yǔ) perimetros
from Greek
源自 希臘語(yǔ)
peri- [peri-]
peri- [前綴，表示.周圍.]
metron [measure] * see meter 2
metron [測(cè)量] *參見 meter2

【引伸】
per.imet.ric
per.imet.rically
adv.（副詞）