Yes, any square is also a rhombus (but not the other way around). Therefore, a square will have the same properties as a rhombus. Namely that all four sides are the same length.
If you were to draw a venn diagram, then the set of squares is at the overlapped intersection of "rhombus" and "rectangle". Check out the diagram below. I have shaded it in blue. Take note the blue region is contained inside the "rhombus" region, meaning that "any square is a rhombus". Furthermore, any square is also a rectangle. Both "rhombus" and "rectangle" are contained in "parallelogram". Meaning any rhombus and any rectangle is a parallelogram.