しかく四角shikakui
1.

Describes an object that has four equal sides and right angles, resembling the geometric shape known as a square.

2.

Refers to a shape that is four-sided, with a flat, even surface and straight edges, creating a rectangular appearance.

3.

Indicates the quality of having a four-cornered outline, often associated with the measurements and angles found in geometric figures.

Example:

必要なのは四角いテーブルで、円卓ではない。