A rhombus.
Its a diamond :]
A rhombus
The rectangle
A shape that has four right angles is a rectangle. If all four sides are equal in length, then it is a square.
a Rhombus...
A rhombus.
The shape you're describing is a rhombus. A rhombus has four sides of equal length, but its angles are not constrained to be right angles, meaning they can be acute or obtuse. This characteristic distinguishes it from a square, which has both equal side lengths and right angles.
rectangle
square
octagon
A shape with four sides that are all equal but has no right angles is a rhombus. In a rhombus, opposite angles are equal, and the sides are of equal length, but the angles are not necessarily 90 degrees. This gives it a distinctive slanted appearance. A square is a special case of a rhombus where all angles are right angles.
This is a parallelogram called a rectangle. A square has four right angles and four sides that are equal in length.