noun
neighbourhood; vicinity; surrounding area
Refers to the area around a particular place; often used in descriptions of a location's surroundings.
この四辺にはコンビニがたくさんある。
There are many convenience stores in this neighbourhood.
noun
all sides; every direction; frontiers
Used for the four directions or all sides of a country or region; can imply borders or frontiers.
その国は四辺を海に囲まれている。
The country is surrounded by sea on all sides.
noun
Specifically refers to the four edges of a square, rectangle, or similar shape.
正方形の四辺の長さは等しい。
The four sides of a square are equal in length.