A quadrilateral is a shape that has 4 sides on it. Remember 'quad' means 4.
Here is a list of the most common quadrilateral shapes.
A square has 4 equal sides and 4 equal angles.
A rectangle has 2 sets of 2 equal sides and 4 equal angles.
A parallelogram has two sets of two equal sides and 2 sets of two equal angles.
A trapezium has one set of equal sides and the other two are different. It has two sets of two equal angles.
A rhombus has 4 equal sides and 2 sets of 2 equal angles.