An equilateral shape would have equal and opposite sides.
Rectangle
A parallelogram is a four sided shape where opposite sides are parallel and equal lengths. If you mean that ALL sides are equal lengths, you are looking for a rhombus.
This just means that opposite sides in a shape (sides that 'look' at each other) are of equal lengths.
an perticulogram
circle
square + rectangle
A parallelogram is a quadrilateral with opposite sides that are parallel and equal in length, and opposite angles that are equal. Two ways to describe a parallelogram could be as a shape with opposite sides that are both parallel and equal in length, or as a shape with opposite angles that are equal.
A square has 4 equal sides with opposite angles that are equal.
trapizoid
polygon
A parallelogram