If something is on the periphery of an area, place, or thing, it is on the edge of it.
例句
Geographically, the UK is on the periphery of Europe, while Paris is at the heart of the continent...從地理位置上講，英國處于歐洲邊緣，而巴黎卻位于歐洲大陸的中心位置。Taste buds are concentrated at the tip and rear of the tongue and around its periphery.味蕾集中于舌尖、舌根和舌頭兩側。
N-COUNT
（學科、興趣的）邊緣，次要部分
The periphery of a subject or area of interest is the part of it that is not considered to be as important or basic as the main part.
例句
The sociological study of religion moved from the centre to the periphery of sociology.宗教的社會學研究從社會學的中心學科變成了邊緣學科。
英漢詞典釋義
n.
外圍；邊緣；周圍；外圍
Other animals were depicted on the periphery of the group.其他動物在群像的外圍加以修飾。