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けいかいしながら黒いたて物に入っていきました。
Koichi went into a black building, cautious of his surroundings.
富士山の火口の周囲は約三キロメートルで、深さは二百三十七メートルだと聞きました。
I was told that Mt. Fuji’s crater is about three kilometers around and two hundred and thirty-seven meters deep.