Perimeter, Circumference, Surroundings, Environs
noun, の adjective
The circumference that surrounds us is the perimeter of the area. Do not cross it.
しゅうい
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
あの女性の周囲にはいつもヤクザ風の男がいる。
There are always yakuza-type men surrounding that lady.
コウイチは周囲の目を気にしながら黒いビルに入っていきました。
Koichi went into a black building, cautious of his surroundings.
周囲の人のこと、もうちょっと考えた方がいいんじゃない?
Maybe you should consider the people around you a little more?