Tetragon

Tetragon is a plane figure with four straight sides and angles.

In geometry a quadrilateral is a four-sided polygon, having four edges (sides) and four corners (vertices).

It is also called a tetragon, derived from Greek «tetra» meaning «four» and «gon» meaning «corner» or «angle»

The only regular (all sides equal and all angles equal) quadrilateral is a square. So all other quadrilaterals are irregular.

https://en.wikipedia.org/wiki/File:Six_Quadrilaterals.svg

https://en.wikipedia.org/wiki/File:Quadrilaterals.svg

In daily life we think of a square as not being a rectangle but in mathematics it is.
A square is a rectangle with equal sides.